diff --git a/binaries/data/mods/public/art/textures/ui/session/portraits/technologies/diaspora.png b/binaries/data/mods/public/art/textures/ui/session/portraits/technologies/diaspora.png
new file mode 100644
index 0000000000..19bffc55fd
--- /dev/null
+++ b/binaries/data/mods/public/art/textures/ui/session/portraits/technologies/diaspora.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9ee781144e25c4e0b6070a5d9ec5feae0050cfd9f72ba40b73f6d16d74751085
+size 33234
diff --git a/binaries/data/mods/public/gui/session/selection_panels.js b/binaries/data/mods/public/gui/session/selection_panels.js
index b00326e825..b836dafefe 100644
--- a/binaries/data/mods/public/gui/session/selection_panels.js
+++ b/binaries/data/mods/public/gui/session/selection_panels.js
@@ -224,8 +224,9 @@ g_SelectionPanels.Command = {
 	},
 	"setGraphics": function(data)
 	{
-		data.icon.sprite = "stretched:session/icons/" + data.item.icon;
 		data.button.enabled = controlsPlayer(data.unitEntState.player);
+		let grayscale = data.button.enabled ? "" : "grayscale:";
+		data.icon.sprite = "stretched:" + grayscale + "session/icons/" + data.item.icon;
 	},
 	"setPosition": function(data)
 	{
@@ -280,8 +281,9 @@ g_SelectionPanels.AllyCommand = {
 	},
 	"setGraphics": function(data)
 	{
-		data.icon.sprite = "stretched:session/icons/" + data.item.icon;
-		data.button.enabled = data.item.count > 0;
+		data.button.enabled = data.item.count != undefined && data.item.count > 0;
+		let grayscale = data.button.enabled ? "" : "grayscale:";
+		data.icon.sprite = "stretched:" + grayscale + "session/icons/" + data.item.icon;
 	},
 	"setPosition": function(data)
 	{
diff --git a/binaries/data/mods/public/gui/session/unit_actions.js b/binaries/data/mods/public/gui/session/unit_actions.js
index 4f4f0f2812..6238e4a57f 100644
--- a/binaries/data/mods/public/gui/session/unit_actions.js
+++ b/binaries/data/mods/public/gui/session/unit_actions.js
@@ -270,9 +270,15 @@ var unitActions =
 		},
 		"getActionInfo": function(entState, targetState)
 		{
-			if (!targetState.resourceDropsite)
+			if (!targetState.resourceDropsite || !targetState.resourceDropsite.sharable)
 				return false;
-			if (!playerCheck(entState, targetState, ["Player"]))
+			var playerState = GetSimState().players[entState.player];
+			if (playerState.hasSharedDropsites && targetState.resourceDropsite.shared)
+			{
+				if (!playerCheck(entState, targetState, ["Player", "MutualAlly"]))
+					return false;
+			}
+			else if (!playerCheck(entState, targetState, ["Player"]))
 				return false;
 			if (!entState.resourceCarrying || !entState.resourceCarrying.length)
 				return false;
@@ -872,7 +878,7 @@ var g_EntityCommands =
 		},
 	},
 	// Trading
-	 "select-trading-goods": {
+	"select-trading-goods": {
 		"getInfo": function(entState)
 		{
 			if (!hasClass(entState, "Market"))
@@ -887,6 +893,34 @@ var g_EntityCommands =
 			toggleTrade();
 		},
 	},
+	// Dropsite sharing
+	"share-dropsite": {
+		"getInfo": function(entState)
+		{
+			if (!entState.resourceDropsite || !entState.resourceDropsite.sharable)
+				return false;
+			let playerState = GetSimState().players[entState.player];
+			if (!playerState.isMutualAlly.some((e, i) => e && i != entState.player))
+				return false;
+			if (entState.resourceDropsite.shared)
+				return {
+					"tooltip": translate("Press to prevent allies from using this dropsite"),
+					"icon": "lock_unlocked.png"
+				};
+			return {
+				"tooltip": translate("Press to allow allies to use this dropsite"),
+				"icon": "lock_locked.png"
+			};
+		},
+		"execute": function(entState)
+		{
+			Engine.PostNetworkCommand({
+				"type": "set-dropsite-sharing",
+				"entities": [entState.id],
+				"shared": !entState.resourceDropsite.shared
+			});
+		},
+	}
 };
 
 var g_AllyEntityCommands =
@@ -923,6 +957,29 @@ var g_AllyEntityCommands =
 			unloadAllByOwner();
 		},
 	},
+	// Dropsite sharing
+	"share-dropsite": {
+		"getInfo": function(entState)
+		{
+			if (!GetSimState().players[Engine.GetPlayerID()].hasSharedDropsites)
+				return false;
+			if (!entState.resourceDropsite || !entState.resourceDropsite.sharable)
+				return false;
+			if (entState.resourceDropsite.shared)
+				return {
+					"tooltip": translate("You are allowed to use this dropsite"),
+					"icon": "lock_unlocked.png"
+				};
+			return {
+				"tooltip": translate("The use of this dropsite is prohibited"),
+				"icon": "lock_locked.png"
+			};
+		},
+		"execute": function(entState)
+		{
+			// This command button is always disabled
+		},
+	}
 };
 
 function playerCheck(entState, targetState, validPlayers)
diff --git a/binaries/data/mods/public/simulation/ai/petra/baseManager.js b/binaries/data/mods/public/simulation/ai/petra/baseManager.js
index d8e22a977a..97dc211db4 100644
--- a/binaries/data/mods/public/simulation/ai/petra/baseManager.js
+++ b/binaries/data/mods/public/simulation/ai/petra/baseManager.js
@@ -264,6 +264,14 @@ m.BaseManager.prototype.assignResourceToDropsite = function (gameState, dropsite
 			});
 		} */
 	}
+
+	// Allows all allies to use this dropsite except if base anchor to be sure to keep
+	// a minimum of resources for this base
+	Engine.PostCommand(PlayerID, {
+		"type": "set-dropsite-sharing",
+		"entities": [dropsiteId],
+		"shared": dropsiteId !== this.anchorId
+	});
 };
 
 // completely remove the dropsite resources from our list.
diff --git a/binaries/data/mods/public/simulation/components/GuiInterface.js b/binaries/data/mods/public/simulation/components/GuiInterface.js
index 8dd6f81a78..9c9a89a1a0 100644
--- a/binaries/data/mods/public/simulation/components/GuiInterface.js
+++ b/binaries/data/mods/public/simulation/components/GuiInterface.js
@@ -106,6 +106,7 @@ GuiInterface.prototype.GetSimulationState = function(player)
 			"teamsLocked": cmpPlayer.GetLockTeams(),
 			"cheatsEnabled": cmpPlayer.GetCheatsEnabled(),
 			"disabledTemplates": cmpPlayer.GetDisabledTemplates(),
+			"hasSharedDropsites": cmpPlayer.HasSharedDropsites(),
 			"phase": phase,
 			"isAlly": allies,
 			"isMutualAlly": mutualAllies,
@@ -516,7 +517,9 @@ GuiInterface.prototype.GetExtendedEntityState = function(player, ent)
 	let cmpResourceDropsite = Engine.QueryInterface(ent, IID_ResourceDropsite);
 	if (cmpResourceDropsite)
 		ret.resourceDropsite = {
-			"types": cmpResourceDropsite.GetTypes()
+			"types": cmpResourceDropsite.GetTypes(),
+			"sharable": cmpResourceDropsite.IsSharable(),
+			"shared": cmpResourceDropsite.IsShared()
 		};
 
 	let cmpPromotion = Engine.QueryInterface(ent, IID_Promotion);
diff --git a/binaries/data/mods/public/simulation/components/Player.js b/binaries/data/mods/public/simulation/components/Player.js
index 0458ee1055..dceb2db4c3 100644
--- a/binaries/data/mods/public/simulation/components/Player.js
+++ b/binaries/data/mods/public/simulation/components/Player.js
@@ -3,6 +3,9 @@ function Player() {}
 Player.prototype.Schema =
 	"<element name='SharedLosTech' a:help='Allies will share los when this technology is researched. Leave empty to never share LOS.'>" +
 		"<text/>" +
+	"</element>" +
+	"<element name='SharedDropsitesTech' a:help='Allies will share dropsites when this technology is researched. Leave empty to never share dropsites.'>" +
+		"<text/>" +
 	"</element>";
 
 Player.prototype.Init = function()
@@ -31,6 +34,7 @@ Player.prototype.Init = function()
 	this.teamsLocked = false;
 	this.state = "active"; // game state - one of "active", "defeated", "won"
 	this.diplomacy = [];	// array of diplomatic stances for this player with respect to other players (including gaia and self)
+	this.sharedDropsites = false;
 	this.formations = [];
 	this.startCam = undefined;
 	this.controlAllUnits = false;
@@ -507,6 +511,11 @@ Player.prototype.HasStartingCamera = function()
 	return (this.startCam !== undefined);
 };
 
+Player.prototype.HasSharedDropsites = function()
+{
+	return this.sharedDropsites;
+};
+
 Player.prototype.SetControlAllUnits = function(c)
 {
 	this.controlAllUnits = c;
@@ -680,6 +689,8 @@ Player.prototype.OnResearchFinished = function(msg)
 {
 	if (msg.tech == this.template.SharedLosTech)
 		this.UpdateSharedLos();
+	else if (msg.tech == this.template.SharedDropsitesTech)
+		this.sharedDropsites = true;
 };
 
 Player.prototype.OnDiplomacyChanged = function()
diff --git a/binaries/data/mods/public/simulation/components/ResourceDropsite.js b/binaries/data/mods/public/simulation/components/ResourceDropsite.js
index ee6451994b..c44dc45805 100644
--- a/binaries/data/mods/public/simulation/components/ResourceDropsite.js
+++ b/binaries/data/mods/public/simulation/components/ResourceDropsite.js
@@ -12,9 +12,16 @@ ResourceDropsite.prototype.Schema =
 				"</choice>" +
 			"</zeroOrMore>" +
 		"</list>" +
+	"</element>" +
+	"<element name='Sharable' a:help='Allows allies to use this entity.'>" +
+		"<data type='boolean'/>" +
 	"</element>";
 
-ResourceDropsite.prototype.Serialize = null;
+ResourceDropsite.prototype.Init = function()
+{
+	this.sharable = this.template.Sharable == "true";
+	this.shared = false;
+};
 
 /**
  * Returns the list of resource types accepted by this dropsite.
@@ -33,4 +40,20 @@ ResourceDropsite.prototype.AcceptsType = function(type)
 	return this.GetTypes().indexOf(type) != -1;
 };
 
+ResourceDropsite.prototype.IsSharable = function()
+{
+	return this.sharable;
+};
+
+ResourceDropsite.prototype.IsShared = function()
+{
+	return this.shared;
+};
+
+ResourceDropsite.prototype.SetSharing = function(value)
+{
+	if (this.sharable)
+		this.shared = value;
+};
+
 Engine.RegisterComponentType(IID_ResourceDropsite, "ResourceDropsite", ResourceDropsite);
diff --git a/binaries/data/mods/public/simulation/components/UnitAI.js b/binaries/data/mods/public/simulation/components/UnitAI.js
index 2ce6889fb4..306d47e9a7 100644
--- a/binaries/data/mods/public/simulation/components/UnitAI.js
+++ b/binaries/data/mods/public/simulation/components/UnitAI.js
@@ -4061,8 +4061,17 @@ UnitAI.prototype.FindNearestDropsite = function(genericType)
 	if (!cmpOwnership || cmpOwnership.GetOwner() == -1)
 		return undefined;
 
-	// Find dropsites owned by this unit's player
-	var players = [cmpOwnership.GetOwner()];
+	// Find dropsites owned by this unit's player or allied ones if allowed
+	var owner = cmpOwnership.GetOwner();
+	var players = [owner];
+	var cmpPlayer = QueryOwnerInterface(this.entity);
+	if (cmpPlayer && cmpPlayer.HasSharedDropsites())
+	{
+		let cmpPlayerManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_PlayerManager);
+		for (let i = 1; i < cmpPlayerManager.GetNumPlayers(); ++i)
+			if (i != owner && cmpPlayer.IsMutualAlly(i))
+				players.push(i);
+	}
 
 	var cmpRangeManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_RangeManager);
 	var nearby = cmpRangeManager.ExecuteQuery(this.entity, 0, -1, players, IID_ResourceDropsite);
@@ -4072,7 +4081,13 @@ UnitAI.prototype.FindNearestDropsite = function(genericType)
 	if (excludeLand)
 		nearby = nearby.filter(e => Engine.QueryInterface(e, IID_Identity).HasClass("Naval"));
 
-	return nearby.find(ent => Engine.QueryInterface(ent, IID_ResourceDropsite).AcceptsType(genericType));
+	return nearby.find(ent => {
+		let cmpResourceDropsite = Engine.QueryInterface(ent, IID_ResourceDropsite);
+		if (!cmpResourceDropsite.AcceptsType(genericType))
+			return false;
+		let cmpOwnership = Engine.QueryInterface(ent, IID_Ownership);
+		return cmpOwnership.GetOwner() == owner || cmpResourceDropsite.IsShared();
+	});
 };
 
 /**
@@ -5753,9 +5768,13 @@ UnitAI.prototype.CanReturnResource = function(target, checkCarriedResource)
 			return false;
 	}
 
-	// Verify that the dropsite is owned by this entity's player
+	// Verify that the dropsite is owned by this entity's player (or an a mutual allied if allowed)
 	var cmpOwnership = Engine.QueryInterface(this.entity, IID_Ownership);
-	return cmpOwnership && IsOwnedByPlayer(cmpOwnership.GetOwner(), target);
+	var cmpPlayer = QueryOwnerInterface(this.entity);
+	if (cmpOwnership && IsOwnedByPlayer(cmpOwnership.GetOwner(), target))
+		return true;
+	return cmpPlayer && cmpPlayer.HasSharedDropsites() && cmpResourceDropsite.IsShared() &&
+	       cmpOwnership && IsOwnedByMutualAllyOfPlayer(cmpOwnership.GetOwner(), target);
 };
 
 UnitAI.prototype.CanTrade = function(target)
diff --git a/binaries/data/mods/public/simulation/data/technologies/unlock_shared_dropsites.json b/binaries/data/mods/public/simulation/data/technologies/unlock_shared_dropsites.json
new file mode 100644
index 0000000000..f05631a204
--- /dev/null
+++ b/binaries/data/mods/public/simulation/data/technologies/unlock_shared_dropsites.json
@@ -0,0 +1,13 @@
+{
+	"genericName": "Diaspora",
+	"description": "The extension of trade leads to the permanent establishment of storekeepers and their families in foreign countries, allowing them to exploit these countries wealth.",
+	"cost": { "food": 200, "wood": 200, "stone": 100, "metal": 100 },
+	"requirements": { "class": "Trader", "number": 3 },
+	"requirementsTooltip": "Requires 3 Traders",
+	"supersedes": "unlock_shared_los",
+	"icon": "diaspora.png",
+	"researchTime": 40,
+	"tooltip": "Player can use his allies dropsites.",
+	"modifications": [{ "value": "Player/sharedDropsites", "replace": true }],
+	"soundComplete": "interface/alarm/alarm_upgradearmory.xml"
+}
diff --git a/binaries/data/mods/public/simulation/helpers/Commands.js b/binaries/data/mods/public/simulation/helpers/Commands.js
index aaf99cc9a6..4189a2f625 100644
--- a/binaries/data/mods/public/simulation/helpers/Commands.js
+++ b/binaries/data/mods/public/simulation/helpers/Commands.js
@@ -685,6 +685,16 @@ var g_Commands = {
 		// Currently nothing. Triggers can read it anyway, and send this
 		// message to any component you like.
 	},
+
+	"set-dropsite-sharing": function(player, cmd, data)
+	{
+		for (let ent of data.entities)
+		{
+			let cmpResourceDropsite = Engine.QueryInterface(ent, IID_ResourceDropsite);
+			if (cmpResourceDropsite && cmpResourceDropsite.IsSharable())
+				cmpResourceDropsite.SetSharing(cmd.shared);
+		}
+	},
 };
 
 /**
diff --git a/binaries/data/mods/public/simulation/templates/special/player.xml b/binaries/data/mods/public/simulation/templates/special/player.xml
index d25510b1bc..c18e69f649 100644
--- a/binaries/data/mods/public/simulation/templates/special/player.xml
+++ b/binaries/data/mods/public/simulation/templates/special/player.xml
@@ -55,6 +55,7 @@
   </Identity>
   <Player>
     <SharedLosTech>unlock_shared_los</SharedLosTech>
+    <SharedDropsitesTech>unlock_shared_dropsites</SharedDropsitesTech>
   </Player>
   <StatisticsTracker/>
   <TechnologyManager/>
diff --git a/binaries/data/mods/public/simulation/templates/special/player_gaia.xml b/binaries/data/mods/public/simulation/templates/special/player_gaia.xml
index 441b7c051c..1edff0a877 100644
--- a/binaries/data/mods/public/simulation/templates/special/player_gaia.xml
+++ b/binaries/data/mods/public/simulation/templates/special/player_gaia.xml
@@ -2,5 +2,6 @@
 <Entity>
   <Player>
     <SharedLosTech/>
+    <SharedDropsitesTech/>
   </Player>
 </Entity>
diff --git a/binaries/data/mods/public/simulation/templates/structures/brit_crannog.xml b/binaries/data/mods/public/simulation/templates/structures/brit_crannog.xml
index 00153ccd6e..82bba4696a 100644
--- a/binaries/data/mods/public/simulation/templates/structures/brit_crannog.xml
+++ b/binaries/data/mods/public/simulation/templates/structures/brit_crannog.xml
@@ -47,6 +47,7 @@
   </RallyPointRenderer>
   <ResourceDropsite>
     <Types>food wood stone metal</Types>
+    <Sharable>true</Sharable>
   </ResourceDropsite>
   <VisualActor>
     <Actor>structures/britons/crannog.xml</Actor>
diff --git a/binaries/data/mods/public/simulation/templates/template_structure_civic_civil_centre.xml b/binaries/data/mods/public/simulation/templates/template_structure_civic_civil_centre.xml
index 472d6ee9c3..c37eeeb214 100644
--- a/binaries/data/mods/public/simulation/templates/template_structure_civic_civil_centre.xml
+++ b/binaries/data/mods/public/simulation/templates/template_structure_civic_civil_centre.xml
@@ -68,10 +68,7 @@
   <Identity>
     <GenericName>Civic Center</GenericName>
     <Tooltip>Build to acquire large tracts of territory. Train citizens. Garrison: 20.</Tooltip>
-    <Classes datatype="tokens">
-      Defensive
-      CivCentre
-    </Classes>
+    <Classes datatype="tokens">Defensive CivCentre</Classes>
     <VisibleClasses datatype="tokens">CivilCentre</VisibleClasses>
     <Icon>structures/civic_centre.png</Icon>
   </Identity>
@@ -97,6 +94,7 @@
   </ProductionQueue>
   <ResourceDropsite>
     <Types>food wood stone metal</Types>
+    <Sharable>true</Sharable>
   </ResourceDropsite>
   <Sound>
     <SoundGroups>
@@ -104,9 +102,9 @@
       <constructed>interface/complete/building/complete_civ_center.xml</constructed>
       <attack>attack/weapon/arrowfly.xml</attack>
       <death>attack/destruction/building_collapse_large.xml</death>
-	  <alert0>interface/alarm/alarm_alert_0.xml</alert0>
-	  <alert1>interface/alarm/alarm_alert_1.xml</alert1>
-	  <alert2>interface/alarm/alarm_alert_2.xml</alert2>
+      <alert0>interface/alarm/alarm_alert_0.xml</alert0>
+      <alert1>interface/alarm/alarm_alert_1.xml</alert1>
+      <alert2>interface/alarm/alarm_alert_2.xml</alert2>
     </SoundGroups>
   </Sound>
   <TerritoryInfluence>
diff --git a/binaries/data/mods/public/simulation/templates/template_structure_economic_farmstead.xml b/binaries/data/mods/public/simulation/templates/template_structure_economic_farmstead.xml
index ed4371a52c..552aa151d3 100644
--- a/binaries/data/mods/public/simulation/templates/template_structure_economic_farmstead.xml
+++ b/binaries/data/mods/public/simulation/templates/template_structure_economic_farmstead.xml
@@ -49,6 +49,7 @@
   <RallyPoint disable=""/>
   <ResourceDropsite>
     <Types>food</Types>
+    <Sharable>true</Sharable>
   </ResourceDropsite>
   <Sound>
     <SoundGroups>
diff --git a/binaries/data/mods/public/simulation/templates/template_structure_economic_market.xml b/binaries/data/mods/public/simulation/templates/template_structure_economic_market.xml
index 9f23b9ae5a..99f12c8bb4 100644
--- a/binaries/data/mods/public/simulation/templates/template_structure_economic_market.xml
+++ b/binaries/data/mods/public/simulation/templates/template_structure_economic_market.xml
@@ -51,6 +51,7 @@
     <BatchTimeModifier>0.7</BatchTimeModifier>
     <Technologies datatype="tokens">
       unlock_shared_los
+      unlock_shared_dropsites
       trade_convoys_speed
       trade_convoys_armor
       trade_gain_01
diff --git a/binaries/data/mods/public/simulation/templates/template_structure_economic_storehouse.xml b/binaries/data/mods/public/simulation/templates/template_structure_economic_storehouse.xml
index f8f658804d..ee0235981b 100644
--- a/binaries/data/mods/public/simulation/templates/template_structure_economic_storehouse.xml
+++ b/binaries/data/mods/public/simulation/templates/template_structure_economic_storehouse.xml
@@ -23,12 +23,7 @@
   <Identity>
     <GenericName>Storehouse</GenericName>
     <Tooltip>Dropsite for wood, stone, and metal resources. Research gathering improvements for these resources.</Tooltip>
-    <Classes datatype="tokens">
-	  DropsiteWood
-	  DropsiteMetal
-	  DropsiteStone
-	  -ConquestCritical
-	</Classes>
+    <Classes datatype="tokens">DropsiteWood DropsiteMetal DropsiteStone -ConquestCritical</Classes>
     <VisibleClasses datatype="tokens">Village Storehouse</VisibleClasses>
     <Icon>structures/storehouse.png</Icon>
   </Identity>
@@ -62,6 +57,7 @@
   <RallyPoint disable=""/>
   <ResourceDropsite>
     <Types>wood stone metal</Types>
+    <Sharable>true</Sharable>
   </ResourceDropsite>
   <Sound>
     <SoundGroups>
diff --git a/binaries/data/mods/public/simulation/templates/template_structure_military_dock.xml b/binaries/data/mods/public/simulation/templates/template_structure_military_dock.xml
index d66f9d8f77..0ea502c992 100644
--- a/binaries/data/mods/public/simulation/templates/template_structure_military_dock.xml
+++ b/binaries/data/mods/public/simulation/templates/template_structure_military_dock.xml
@@ -45,6 +45,7 @@
   </RallyPointRenderer>
   <ResourceDropsite>
     <Types>food wood stone metal</Types>
+    <Sharable>true</Sharable>
   </ResourceDropsite>
   <Sound>
     <SoundGroups>
@@ -71,7 +72,7 @@
       armor_ship_hullsheathing
     </Technologies>
   </ProductionQueue>
-  <Vision>
+   <Vision>
     <Range>40</Range>
   </Vision>
   <VisualActor>
diff --git a/binaries/data/mods/public/simulation/templates/units/maur_support_elephant.xml b/binaries/data/mods/public/simulation/templates/units/maur_support_elephant.xml
index 134913c856..09e9b807ec 100644
--- a/binaries/data/mods/public/simulation/templates/units/maur_support_elephant.xml
+++ b/binaries/data/mods/public/simulation/templates/units/maur_support_elephant.xml
@@ -44,6 +44,7 @@
   </Position>
   <ResourceDropsite>
     <Types>food wood stone metal</Types>
+    <Sharable>false</Sharable>
   </ResourceDropsite>
   <Selectable>
     <Overlay>