diff --git a/.idea/misc.xml b/.idea/misc.xml
index e659c40..fcf3066 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -54,7 +54,7 @@
     <ConfirmationsSetting value="0" id="Add" />
     <ConfirmationsSetting value="0" id="Remove" />
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_3" default="false" assert-keyword="false" jdk-15="false" project-jdk-name="Python 2.7.12 virtualenv at ~/Development/metrik/py2-virt" project-jdk-type="Python SDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_3" default="false" assert-keyword="false" jdk-15="false" project-jdk-name="Python 3.5.1 virtualenv at C:\Users\Bradlee Speice\Development\metrik\metrik-virtual" project-jdk-type="Python SDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
   <component name="PythonCompatibilityInspectionAdvertiser">
diff --git a/metrik/__init__.py b/metrik/__init__.py
index 99aa587..ba0e4af 100644
--- a/metrik/__init__.py
+++ b/metrik/__init__.py
@@ -1,2 +1,2 @@
-__version__ = '0.4.1'
+__version__ = '0.4.2'
 __release__ = __version__
\ No newline at end of file
diff --git a/metrik/targets/mongo.py b/metrik/targets/mongo.py
index 9b1045a..d2064ce 100644
--- a/metrik/targets/mongo.py
+++ b/metrik/targets/mongo.py
@@ -4,6 +4,7 @@ from datetime import datetime
 from contextlib import contextmanager
 
 from metrik.conf import get_config
+from metrik import __version__ as version
 
 
 class MongoTarget(Target):
@@ -29,9 +30,12 @@ class MongoTarget(Target):
                 '_id': self.id
             }) is not None
 
-    def persist(self, dict_object):
+    def persist(self, dict_object, present=None):
         id_dict = dict_object
         id_dict['_id'] = self.id
+        id_dict['_metrik_version'] = version
+        id_dict['_created_at'] = (present if present is not None
+                                  else datetime.now())
 
         with self.get_db() as db:
             return db[self.collection].insert_one(id_dict).inserted_id
diff --git a/test/targets/test_mongo_target.py b/test/targets/test_mongo_target.py
index 7fc1779..9814147 100644
--- a/test/targets/test_mongo_target.py
+++ b/test/targets/test_mongo_target.py
@@ -1,10 +1,11 @@
 from pymongo import MongoClient
 from random import randint
+from datetime import datetime, timedelta
 
 from metrik.targets.mongo import MongoTarget
 from metrik.conf import get_config
 from test.mongo_test import MongoTest
-
+from metrik import __version__ as version
 
 class MongoTargetTest(MongoTest):
 
@@ -38,4 +39,23 @@ class MongoTargetTest(MongoTest):
         # Make sure we can trivially scale correctly
         targets = [MongoTarget('test_collection', i) for i in range(10000)]
 
-        self.assertEqual(len(targets), 10000)
\ No newline at end of file
+        self.assertEqual(len(targets), 10000)
+
+    def test_metrik_version_saved(self):
+        t = MongoTarget('test_collection', 1234)
+        t.persist({})
+        r = t.retrieve()
+        assert r['_metrik_version'] == version
+
+    def test_created_at_timestamp(self):
+        present = datetime.now()
+        t = MongoTarget('test_collection', 1234)
+        t.persist({})
+        r = t.retrieve()
+        self.assertGreaterEqual(present, r['_created_at'])
+
+        one_second_past = present - timedelta(seconds=1)
+        t = MongoTarget('test_collection', 1235)
+        t.persist({}, present=one_second_past)
+        r = t.retrieve()
+        self.assertEqual(one_second_past, r['_created_at'])
\ No newline at end of file