diff --git a/MultiversalDiplomacy/Adjudicate/MovementPhaseAdjudicator.cs b/MultiversalDiplomacy/Adjudicate/MovementPhaseAdjudicator.cs
index ce82bed..f8ec92a 100644
--- a/MultiversalDiplomacy/Adjudicate/MovementPhaseAdjudicator.cs
+++ b/MultiversalDiplomacy/Adjudicate/MovementPhaseAdjudicator.cs
@@ -391,10 +391,10 @@ public class MovementPhaseAdjudicator : IPhaseAdjudicator
             OrderHistory history = newHistory[unitOrder.Unit.Season.Designation];
             // TODO does this add every order to every season??
             history.Orders.Add(unitOrder);
-            history.IsDislodgedOutcomes[unitOrder.Unit] = dislodges[unitOrder.Unit].Outcome == true;
+            history.IsDislodgedOutcomes[unitOrder.Unit.Designation] = dislodges[unitOrder.Unit].Outcome == true;
             if (unitOrder is MoveOrder moveOrder)
             {
-                history.DoesMoveOutcomes[moveOrder] = moves[moveOrder].Outcome == true;
+                history.DoesMoveOutcomes[moveOrder.Unit.Designation] = moves[moveOrder].Outcome == true;
             }
         }
 
@@ -494,7 +494,7 @@ public class MovementPhaseAdjudicator : IPhaseAdjudicator
         IEnumerable<MoveOrder> newIncomingMoves = decision.Orders
             .OfType<MoveOrder>()
             .Where(order => order.Season == decision.Season
-                && !world.OrderHistory[order.Season.Designation].DoesMoveOutcomes.ContainsKey(order));
+                && !world.OrderHistory[order.Season.Designation].DoesMoveOutcomes.ContainsKey(order.Unit.Designation));
         foreach (MoveOrder moveOrder in newIncomingMoves)
         {
             DoesMove doesMove = decisions.DoesMove[moveOrder];
@@ -518,7 +518,7 @@ public class MovementPhaseAdjudicator : IPhaseAdjudicator
             // TODO these aren't timeline-specific
             IsDislodged dislodged = decisions.IsDislodged[order.Unit];
             progress |= ResolveDecision(dislodged, world, decisions, depth + 1);
-            if (history.IsDislodgedOutcomes.TryGetValue(order.Unit, out bool previous)
+            if (history.IsDislodgedOutcomes.TryGetValue(order.Unit.Designation, out bool previous)
                 && dislodged.Resolved
                 && dislodged.Outcome != previous)
             {
@@ -535,7 +535,7 @@ public class MovementPhaseAdjudicator : IPhaseAdjudicator
             {
                 DoesMove moves = decisions.DoesMove[moveOrder];
                 progress |= ResolveDecision(moves, world, decisions, depth + 1);
-                if (history.DoesMoveOutcomes.TryGetValue(moveOrder, out bool previousMove)
+                if (history.DoesMoveOutcomes.TryGetValue(moveOrder.Unit.Designation, out bool previousMove)
                     && moves.Resolved
                     && moves.Outcome != previousMove)
                 if (moves.Resolved && moves.Outcome != previousMove)
diff --git a/MultiversalDiplomacy/Model/OrderHistory.cs b/MultiversalDiplomacy/Model/OrderHistory.cs
index 10dbea4..1621473 100644
--- a/MultiversalDiplomacy/Model/OrderHistory.cs
+++ b/MultiversalDiplomacy/Model/OrderHistory.cs
@@ -6,11 +6,17 @@ namespace MultiversalDiplomacy.Model;
 
 public class OrderHistory
 {
-    public List<UnitOrder> Orders;
+    public List<UnitOrder> Orders { get; }
 
-    public Dictionary<Unit, bool> IsDislodgedOutcomes;
+    /// <summary>
+    /// Map from unit designation to dislodge outcome.
+    /// </summary>
+    public Dictionary<string, bool> IsDislodgedOutcomes { get; }
 
-    public Dictionary<MoveOrder, bool> DoesMoveOutcomes;
+    /// <summary>
+    /// Map from designation of the ordered unit to move outcome.
+    /// </summary>
+    public Dictionary<string, bool> DoesMoveOutcomes { get; }
 
     public OrderHistory()
         : this([], [], [])
@@ -18,8 +24,8 @@ public class OrderHistory
 
     public OrderHistory(
         List<UnitOrder> orders,
-        Dictionary<Unit, bool> isDislodgedOutcomes,
-        Dictionary<MoveOrder, bool> doesMoveOutcomes)
+        Dictionary<string, bool> isDislodgedOutcomes,
+        Dictionary<string, bool> doesMoveOutcomes)
     {
         this.Orders = new(orders);
         this.IsDislodgedOutcomes = new(isDislodgedOutcomes);
diff --git a/MultiversalDiplomacyTests/SerializationTest.cs b/MultiversalDiplomacyTests/SerializationTest.cs
index 8a34f3d..c96c033 100644
--- a/MultiversalDiplomacyTests/SerializationTest.cs
+++ b/MultiversalDiplomacyTests/SerializationTest.cs
@@ -64,12 +64,20 @@ public class SerializationTest
         Assert.That(tyr0, Is.NotDislodged);
         setup.UpdateWorld();
 
+        Assert.That(setup.World.OrderHistory["a0"].Orders.Count, Is.GreaterThan(0));
+        Assert.That(setup.World.OrderHistory["a0"].DoesMoveOutcomes.Count, Is.GreaterThan(0));
+        Assert.That(setup.World.OrderHistory["a0"].IsDislodgedOutcomes.Count, Is.GreaterThan(0));
+
         // Serialize and deserialize the world
         string serialized = JsonSerializer.Serialize(setup.World, Options);
         // Console.WriteLine(serialized);
         World reserialized = JsonSerializer.Deserialize<World>(serialized, Options)
             ?? throw new AssertionException("Failed to reserialize world");
 
+        Assert.That(reserialized.OrderHistory["a0"].Orders.Count, Is.GreaterThan(0));
+        Assert.That(reserialized.OrderHistory["a0"].DoesMoveOutcomes.Count, Is.GreaterThan(0));
+        Assert.That(reserialized.OrderHistory["a0"].IsDislodgedOutcomes.Count, Is.GreaterThan(0));
+
         // Resume the test case
         setup = new(reserialized, MovementPhaseAdjudicator.Instance);
         setup[("a", 1)]