diff --git a/js/id/core/connection.js b/js/id/core/connection.js
index e531dd2c4..cccca636c 100644
--- a/js/id/core/connection.js
+++ b/js/id/core/connection.js
@@ -52,7 +52,7 @@ iD.Connection = function() {
             url + '/api/0.6/' + type + '/' + osmID + (type !== 'node' ? '/full' : ''),
             function(err, entities) {
                 event.load(err, {data: entities});
-                if (callback) callback(err, entities && entities[id]);
+                if (callback) callback(err, entities && _.find(entities, function(e) { return e.id === id; }));
             });
     };
 
@@ -137,15 +137,13 @@ iD.Connection = function() {
 
         var root = dom.childNodes[0],
             children = root.childNodes,
-            entities = {};
+            entities = [];
 
-        var i, o, l;
-        for (i = 0, l = children.length; i < l; i++) {
+        for (var i = 0, l = children.length; i < l; i++) {
             var child = children[i],
                 parser = parsers[child.nodeName];
             if (parser) {
-                o = parser(child);
-                entities[o.id] = o;
+                entities.push(parser(child));
             }
         }
 
diff --git a/js/id/core/graph.js b/js/id/core/graph.js
index 029cbdca6..ba11d7f11 100644
--- a/js/id/core/graph.js
+++ b/js/id/core/graph.js
@@ -9,17 +9,10 @@ iD.Graph = function(other, mutable) {
         this.inherited = true;
 
     } else {
-        if (Array.isArray(other)) {
-            var entities = {};
-            for (var i = 0; i < other.length; i++) {
-                entities[other[i].id] = other[i];
-            }
-            other = entities;
-        }
         this.entities = Object.create({});
         this._parentWays = Object.create({});
         this._parentRels = Object.create({});
-        this.rebase(other || {});
+        this.rebase(other || []);
     }
 
     this.transients = {};
@@ -108,11 +101,12 @@ iD.Graph.prototype = {
 
         // Merging of data only needed if graph is the base graph
         if (!this.inherited) {
-            for (i in entities) {
-                if (!base.entities[i]) {
-                    base.entities[i] = entities[i];
-                    this._updateCalculated(undefined, entities[i],
-                            base.parentWays, base.parentRels);
+            for (i = 0; i < entities.length; i++) {
+                var entity = entities[i];
+                if (!base.entities[entity.id]) {
+                    base.entities[entity.id] = entity;
+                    this._updateCalculated(undefined, entity,
+                        base.parentWays, base.parentRels);
                 }
             }
         }
diff --git a/js/id/core/history.js b/js/id/core/history.js
index de8e1c24c..73749aadb 100644
--- a/js/id/core/history.js
+++ b/js/id/core/history.js
@@ -46,7 +46,7 @@ iD.History = function(context) {
                 stack[i].graph.rebase(entities);
             }
 
-            tree.rebase(d3.values(entities));
+            tree.rebase(entities);
 
             dispatch.change(undefined, extent);
         },
diff --git a/js/id/ui/intro.js b/js/id/ui/intro.js
index 91c55358a..8f1f35a39 100644
--- a/js/id/ui/intro.js
+++ b/js/id/ui/intro.js
@@ -23,7 +23,7 @@ iD.ui.intro = function(context) {
         for (var key in introGraph) {
             introGraph[key] = iD.Entity(introGraph[key]);
         }
-        context.history().merge(iD.Graph().load(introGraph).entities);
+        context.history().merge(d3.values(iD.Graph().load(introGraph).entities));
         context.background().bing();
 
         // Block saving
@@ -59,7 +59,7 @@ iD.ui.intro = function(context) {
             navwrap.remove();
             d3.select('.background-layer').style('opacity', opacity);
             context.connection().toggle(true).flush().loadedTiles(loadedTiles);
-            context.history().reset().merge(baseEntities);
+            context.history().reset().merge(d3.values(baseEntities));
             context.background().baseLayerSource(background);
             if (history) context.history().fromJSON(history);
             window.location.replace(hash);
diff --git a/test/spec/actions/merge_polygon.js b/test/spec/actions/merge_polygon.js
index 9da988ee5..5270ce29f 100644
--- a/test/spec/actions/merge_polygon.js
+++ b/test/spec/actions/merge_polygon.js
@@ -1,14 +1,14 @@
 describe("iD.actions.MergePolygon", function () {
     
     function node(id, x, y) {
-        e[id] = iD.Node({ id: id, loc: [x, y] });
+        e.push(iD.Node({ id: id, loc: [x, y] }));
     }
 
     function way(id, nodes) {
-        e[id] = iD.Way({ id: id, nodes: nodes.map(function(n) { return 'n' + n; }) });
+        e.push(iD.Way({ id: id, nodes: nodes.map(function(n) { return 'n' + n; }) }));
     }
 
-    var e = {};
+    var e = [];
 
     node('n0', 0, 0);
     node('n1', 5, 0);
@@ -86,8 +86,8 @@ describe("iD.actions.MergePolygon", function () {
     });
 
     it("moves all tags to the relation", function() {
-        graph = graph.replace(e.w0.update({ tags: { 'building': 'yes' }}));
-        graph = graph.replace(e.w1.update({ tags: { 'natural': 'water' }}));
+        graph = graph.replace(graph.entity('w0').update({ tags: { 'building': 'yes' }}));
+        graph = graph.replace(graph.entity('w1').update({ tags: { 'natural': 'water' }}));
         graph = iD.actions.MergePolygon(['w0', 'w1'], 'r')(graph);
         var r = graph.entity('r');
         expect(graph.entity('w0').tags.building).to.equal(undefined);
@@ -97,7 +97,7 @@ describe("iD.actions.MergePolygon", function () {
     });
 
     it("doesn't copy area tags from ways", function() {
-        graph = graph.replace(e.w0.update({ tags: { 'area': 'yes' }}));
+        graph = graph.replace(graph.entity('w0').update({ tags: { 'area': 'yes' }}));
         graph = iD.actions.MergePolygon(['w0', 'w1'], 'r')(graph);
         var r = graph.entity('r');
         expect(r.tags.area).to.equal(undefined);
diff --git a/test/spec/core/connection.js b/test/spec/core/connection.js
index feb676680..305275fb3 100644
--- a/test/spec/core/connection.js
+++ b/test/spec/core/connection.js
@@ -59,15 +59,15 @@ describe('iD.Connection', function () {
         });
 
         it('parses a node', function (done) {
-            c.loadFromURL('data/node.xml', function (err, graph) {
-                expect(graph.n356552551).to.be.instanceOf(iD.Entity);
+            c.loadFromURL('data/node.xml', function (err, entities) {
+                expect(entities[0]).to.be.instanceOf(iD.Entity);
                 done();
             });
         });
 
         it('parses a way', function (done) {
-            c.loadFromURL('data/way.xml', function (err, graph) {
-                expect(graph.w19698713).to.be.instanceOf(iD.Entity);
+            c.loadFromURL('data/way.xml', function (err, entities) {
+                expect(entities[0]).to.be.instanceOf(iD.Entity);
                 done();
             });
         });
@@ -116,7 +116,7 @@ describe('iD.Connection', function () {
         it('emits a load event', function(done) {
             c.loadEntity('n1');
             c.on('load', function(error, result) {
-                expect(result.data.n1).to.be.an.instanceOf(iD.Node);
+                expect(result.data[0]).to.be.an.instanceOf(iD.Node);
                 done();
             });
 
diff --git a/test/spec/core/graph.js b/test/spec/core/graph.js
index 5df07a336..5fb2bbe6a 100644
--- a/test/spec/core/graph.js
+++ b/test/spec/core/graph.js
@@ -1,11 +1,5 @@
 describe('iD.Graph', function() {
     describe("constructor", function () {
-        it("accepts an entities Object", function () {
-            var entity = iD.Entity(),
-                graph = iD.Graph({'n-1': entity});
-            expect(graph.entity('n-1')).to.equal(entity);
-        });
-
         it("accepts an entities Array", function () {
             var entity = iD.Entity(),
                 graph = iD.Graph([entity]);
@@ -80,14 +74,14 @@ describe('iD.Graph', function() {
         it("preserves existing entities", function () {
             var node = iD.Node({id: 'n'}),
                 graph = iD.Graph([node]);
-            graph.rebase({});
+            graph.rebase([]);
             expect(graph.entity('n')).to.equal(node);
         });
 
         it("includes new entities", function () {
             var node = iD.Node({id: 'n'}),
                 graph = iD.Graph();
-            graph.rebase({'n': node});
+            graph.rebase([node]);
             expect(graph.entity('n')).to.equal(node);
         });
 
@@ -95,13 +89,13 @@ describe('iD.Graph', function() {
             var a = iD.Node({id: 'n'}),
                 b = iD.Node({id: 'n'}),
                 graph = iD.Graph([a]);
-            graph.rebase({'n': b});
+            graph.rebase([b]);
             expect(graph.entity('n')).to.equal(a);
         });
 
         it("inherits entities from base prototypally", function () {
             var graph = iD.Graph();
-            graph.rebase({'n': iD.Node()});
+            graph.rebase([iD.Node()]);
             expect(graph.entities).not.to.have.ownProperty('n');
         });
 
@@ -111,7 +105,7 @@ describe('iD.Graph', function() {
                 w2 = iD.Way({id: 'w2', nodes: ['n']}),
                 graph = iD.Graph([n, w1]);
 
-            graph.rebase({ 'w2': w2 });
+            graph.rebase([w2]);
             expect(graph.parentWays(n)).to.eql([w1, w2]);
             expect(graph._parentWays.hasOwnProperty('n')).to.be.false;
         });
@@ -120,7 +114,7 @@ describe('iD.Graph', function() {
             var n = iD.Node({id: 'n'}),
                 w1 = iD.Way({id: 'w1', nodes: ['n']}),
                 graph = iD.Graph([n, w1]);
-            graph.rebase({ 'w1': w1 });
+            graph.rebase([w1]);
             expect(graph.parentWays(n)).to.eql([w1]);
         });
 
@@ -132,8 +126,8 @@ describe('iD.Graph', function() {
                 graph = iD.Graph([n, w1]),
                 graph2 = graph.replace(w2);
 
-            graph.rebase({ 'w3': w3 });
-            graph2.rebase({ 'w3': w3 });
+            graph.rebase([w3]);
+            graph2.rebase([w3]);
 
             expect(graph2.parentWays(n)).to.eql([w1, w2, w3]);
         });
@@ -146,8 +140,8 @@ describe('iD.Graph', function() {
                 graph = iD.Graph([n1, n2, w1]),
                 graph2 = graph.replace(w2);
 
-            graph.rebase({ 'w1': w1 });
-            graph2.rebase({ 'w1': w1 });
+            graph.rebase([w1]);
+            graph2.rebase([w1]);
 
             expect(graph2.parentWays(n2)).to.eql([]);
         });
@@ -158,8 +152,8 @@ describe('iD.Graph', function() {
                 graph = iD.Graph([n, w1]),
                 graph2 = graph.remove(w1);
 
-            graph.rebase({ 'w1': w1 });
-            graph2.rebase({ 'w1': w1 });
+            graph.rebase([w1]);
+            graph2.rebase([w1]);
 
             expect(graph2.parentWays(n)).to.eql([]);
         });
@@ -170,7 +164,7 @@ describe('iD.Graph', function() {
                 r2 = iD.Relation({id: 'r2', members: [{id: 'n'}]}),
                 graph = iD.Graph([n, r1]);
 
-            graph.rebase({'r2': r2});
+            graph.rebase([r2]);
 
             expect(graph.parentRelations(n)).to.eql([r1, r2]);
             expect(graph._parentRels.hasOwnProperty('n')).to.be.false;
@@ -183,8 +177,8 @@ describe('iD.Graph', function() {
                 graph = iD.Graph([n, r1]),
                 graph2 = graph.replace(r2);
 
-            graph.rebase({ 'r1': r1 });
-            graph2.rebase({ 'r1': r1 });
+            graph.rebase([r1]);
+            graph2.rebase([r1]);
 
             expect(graph2.parentRelations(n)).to.eql([]);
         });
@@ -195,8 +189,8 @@ describe('iD.Graph', function() {
                 graph = iD.Graph([n, r1]),
                 graph2 = graph.remove(r1);
 
-            graph.rebase({ 'r1': r1 });
-            graph2.rebase({ 'r1': r1 });
+            graph.rebase([r1]);
+            graph2.rebase([r1]);
 
             expect(graph2.parentRelations(n)).to.eql([]);
         });
@@ -209,8 +203,8 @@ describe('iD.Graph', function() {
                 graph = iD.Graph([n, r1]),
                 graph2 = graph.replace(r2);
 
-            graph.rebase({'r3': r3});
-            graph2.rebase({'r3': r3});
+            graph.rebase([r3]);
+            graph2.rebase([r3]);
             expect(graph2.parentRelations(n)).to.eql([r1, r2, r3]);
         });
 
@@ -227,7 +221,7 @@ describe('iD.Graph', function() {
             }
 
             expect(numParents(n)).to.equal(1);
-            graph.rebase({w2: w2});
+            graph.rebase([w2]);
             expect(numParents(n)).to.equal(2);
         });
     });
diff --git a/test/spec/core/history.js b/test/spec/core/history.js
index ec584711e..0df9fc5d8 100644
--- a/test/spec/core/history.js
+++ b/test/spec/core/history.js
@@ -19,14 +19,14 @@ describe("iD.History", function () {
     describe("#merge", function () {
         it("merges the entities into all graph versions", function () {
             var n = iD.Node({id: 'n'});
-            history.merge({n: n});
+            history.merge([n]);
             expect(history.graph().entity('n')).to.equal(n);
         });
 
         it("emits a change event with the specified extent", function () {
             var extent = {};
             history.on('change', spy);
-            history.merge({}, extent);
+            history.merge([], extent);
             expect(spy).to.have.been.calledWith(undefined, extent);
         });
     });
@@ -186,14 +186,14 @@ describe("iD.History", function () {
         it("includes modified entities", function () {
             var node1 = iD.Node({id: "n1"}),
                 node2 = node1.update({ tags: { yes: "no" } });
-            history.merge({ n1: node1});
+            history.merge([node1]);
             history.perform(function (graph) { return graph.replace(node2); });
             expect(history.changes().modified).to.eql([node2]);
         });
 
         it("includes deleted entities", function () {
             var node = iD.Node({id: "n1"});
-            history.merge({ n1: node });
+            history.merge([node]);
             history.perform(function (graph) { return graph.remove(node); });
             expect(history.changes().deleted).to.eql([node]);
         });
@@ -231,7 +231,7 @@ describe("iD.History", function () {
     describe("#toJSON", function() {
         it("generates v2 JSON", function() {
             var node = iD.Node({id: 'n-1'});
-            history.merge({n1: iD.Node({id: 'n1'})});
+            history.merge([iD.Node({id: 'n1'})]);
             history.perform(iD.actions.AddEntity(node));
             var json = JSON.parse(history.toJSON());
             expect(json.version).to.eql(2);
@@ -283,7 +283,7 @@ describe("iD.History", function () {
                 "index": 1
             };
             history.fromJSON(JSON.stringify(json));
-            history.merge({n1: iD.Node({id: 'n1'})});
+            history.merge([iD.Node({id: 'n1'})]);
             expect(history.graph().hasEntity('n1')).to.be.undefined;
             expect(history.undoAnnotation()).to.eql("Deleted a point.");
             expect(history.imageryUsed()).to.eql(["Bing"]);
@@ -344,7 +344,7 @@ describe("iD.History", function () {
                 "index": 1
             };
             history.fromJSON(JSON.stringify(json));
-            history.merge({n1: iD.Node({id: 'n1'})});
+            history.merge([iD.Node({id: 'n1'})]);
             expect(history.graph().hasEntity('n1')).to.be.undefined;
             expect(history.undoAnnotation()).to.eql("Deleted a point.");
             expect(history.imageryUsed()).to.eql(["Bing"]);
diff --git a/test/spec/core/tree.js b/test/spec/core/tree.js
index 3c615fb2d..89a9c761a 100644
--- a/test/spec/core/tree.js
+++ b/test/spec/core/tree.js
@@ -5,7 +5,7 @@ describe("iD.Tree", function() {
                 tree = iD.Tree(graph),
                 node = iD.Node({id: 'n', loc: [1, 1]});
 
-            graph.rebase({n: node});
+            graph.rebase([node]);
             tree.rebase([node]);
 
             expect(tree.intersects(iD.geo.Extent([0, 0], [2, 2]), graph)).to.eql([node]);
@@ -17,11 +17,11 @@ describe("iD.Tree", function() {
                 node = iD.Node({id: 'n', loc: [1, 1]}),
                 extent = iD.geo.Extent([0, 0], [2, 2]);
 
-            graph.rebase({n: node});
+            graph.rebase([node]);
             tree.rebase([node]);
             expect(tree.intersects(extent, graph)).to.eql([node]);
 
-            graph.rebase({n: node});
+            graph.rebase([node]);
             tree.rebase([node]);
             expect(tree.intersects(extent, graph)).to.eql([node]);
         });
@@ -63,11 +63,11 @@ describe("iD.Tree", function() {
                 relation = iD.Relation({id: 'r', members: [{id: 'n1'}, {id: 'n2'}]}),
                 extent = iD.geo.Extent([0.5, 0.5], [1.5, 1.5]);
 
-            graph.rebase({r: relation, n1: n1});
+            graph.rebase([relation, n1]);
             tree.rebase([relation, n1]);
             expect(tree.intersects(extent, graph)).to.eql([]);
 
-            graph.rebase({n2: n2});
+            graph.rebase([n2]);
             tree.rebase([n2]);
             expect(tree.intersects(extent, graph)).to.eql([n2, relation]);
         });
@@ -83,8 +83,8 @@ describe("iD.Tree", function() {
 
             expect(tree.intersects(extent, graph)).to.eql([]);
 
-            base.rebase({n: node});
-            graph.rebase({n: node});
+            base.rebase([node]);
+            graph.rebase([node]);
             tree.rebase([node]);
             expect(tree.intersects(extent, graph)).to.eql([node, way]);
         });
@@ -140,7 +140,7 @@ describe("iD.Tree", function() {
             var graph = base.replace(node).remove(node);
             expect(tree.intersects(extent, graph)).to.eql([]);
 
-            base.rebase({n: node});
+            base.rebase([node]);
             tree.rebase([node]);
             expect(tree.intersects(extent, graph)).to.eql([]);
         });
@@ -156,8 +156,8 @@ describe("iD.Tree", function() {
             var graph = base.replace(r1).replace(r2);
             expect(tree.intersects(extent, graph)).to.eql([]);
 
-            base.rebase({n: node});
-            graph.rebase({n: node});
+            base.rebase([node]);
+            graph.rebase([node]);
             tree.rebase([node]);
             expect(tree.intersects(extent, graph)).to.eql([node, r1, r2]);
         });
diff --git a/test/spec/ui/raw_tag_editor.js b/test/spec/ui/raw_tag_editor.js
index 0d53cb609..d97766c4d 100644
--- a/test/spec/ui/raw_tag_editor.js
+++ b/test/spec/ui/raw_tag_editor.js
@@ -16,7 +16,7 @@ describe('iD.ui.RawTagEditor', function() {
     beforeEach(function () {
         entity = iD.Node({id: "n12345"});
         context = iD();
-        context.history().merge({n12345: entity});
+        context.history().merge([entity]);
         render({highway: 'residential'});
     });