diff --git a/federation/entities/activitypub/mappers.py b/federation/entities/activitypub/mappers.py
index 7cfb48e..8d023af 100644
--- a/federation/entities/activitypub/mappers.py
+++ b/federation/entities/activitypub/mappers.py
@@ -1,3 +1,4 @@
+import logging
 from typing import List, Callable, Dict, Union
 
 from federation.entities.activitypub.entities import ActivitypubFollow, ActivitypubProfile, ActivitypubAccept
@@ -5,6 +6,9 @@ from federation.entities.base import Follow, Profile, Accept
 from federation.entities.mixins import BaseEntity
 from federation.types import UserType
 
+logger = logging.getLogger("federation")
+
+
 MAPPINGS = {
     "Accept": ActivitypubAccept,
     "Follow": ActivitypubFollow,
@@ -23,10 +27,24 @@ def element_to_objects(payload: Dict) -> List:
 
     transformed = transform_attributes(payload, cls)
     entity = cls(**transformed)
+    # Add protocol name
+    entity._source_protocol = "activitypub"
+    # Save element object to entity for possible later use
+    entity._source_object = payload
 
     if hasattr(entity, "post_receive"):
         entity.post_receive()
 
+    try:
+        entity.validate()
+    except ValueError as ex:
+        logger.error("Failed to validate entity %s: %s", entity, ex, extra={
+            "transformed": transformed,
+        })
+        return []
+    # Extract mentions
+    entity._mentions = entity.extract_mentions()
+
     entities.append(entity)
 
     return entities
diff --git a/federation/tests/entities/activitypub/test_mappers.py b/federation/tests/entities/activitypub/test_mappers.py
index 6846021..9782748 100644
--- a/federation/tests/entities/activitypub/test_mappers.py
+++ b/federation/tests/entities/activitypub/test_mappers.py
@@ -5,7 +5,7 @@ import pytest
 from federation.entities.activitypub.entities import ActivitypubFollow, ActivitypubAccept, ActivitypubProfile
 from federation.entities.activitypub.mappers import message_to_objects, get_outbound_entity
 from federation.entities.base import Accept, Follow, Profile
-from federation.tests.fixtures.payloads import ACTIVITYPUB_FOLLOW, ACTIVITYPUB_PROFILE
+from federation.tests.fixtures.payloads import ACTIVITYPUB_FOLLOW, ACTIVITYPUB_PROFILE, ACTIVITYPUB_PROFILE_INVALID
 
 
 class TestActivitypubEntityMappersReceive:
@@ -180,31 +180,20 @@ class TestActivitypubEntityMappersReceive:
         assert entity.raw_content == "Important note here"
         assert entity.entity_type == "Comment"
 
-    @pytest.mark.skip
+    @patch("federation.entities.activitypub.mappers.logger.error")
     def test_invalid_entity_logs_an_error(self, mock_logger):
-        entities = message_to_objects(DIASPORA_POST_INVALID, "alice@alice.diaspora.example.org")
+        entities = message_to_objects(ACTIVITYPUB_PROFILE_INVALID, "http://example.com/1234")
         assert len(entities) == 0
         assert mock_logger.called
 
-    @pytest.mark.skip
     def test_adds_source_protocol_to_entity(self):
-        entities = message_to_objects(DIASPORA_POST_SIMPLE, "alice@alice.diaspora.example.org")
-        assert entities[0]._source_protocol == "diaspora"
+        entities = message_to_objects(ACTIVITYPUB_PROFILE, "http://example.com/1234")
+        assert entities[0]._source_protocol == "activitypub"
 
-    @pytest.mark.skip
-    def test_source_object(self, mock_validate):
-        entities = message_to_objects(DIASPORA_POST_COMMENT, "alice@alice.diaspora.example.org",
-                                      sender_key_fetcher=Mock())
+    def test_source_object(self):
+        entities = message_to_objects(ACTIVITYPUB_PROFILE, "http://example.com/1234")
         entity = entities[0]
-        assert entity._source_object == etree.tostring(etree.fromstring(DIASPORA_POST_COMMENT))
-
-    @pytest.mark.skip
-    def test_element_to_objects_calls_sender_key_fetcher(self, mock_validate):
-        mock_fetcher = Mock()
-        message_to_objects(DIASPORA_POST_COMMENT, "alice@alice.diaspora.example.org", mock_fetcher)
-        mock_fetcher.assert_called_once_with(
-            "alice@alice.diaspora.example.org",
-        )
+        assert entity._source_object == ACTIVITYPUB_PROFILE
 
     @pytest.mark.skip
     def test_element_to_objects_calls_retrieve_remote_profile(self, mock_retrieve, mock_validate):
diff --git a/federation/tests/fixtures/payloads/activitypub.py b/federation/tests/fixtures/payloads/activitypub.py
index e0a1f35..28aed89 100644
--- a/federation/tests/fixtures/payloads/activitypub.py
+++ b/federation/tests/fixtures/payloads/activitypub.py
@@ -83,3 +83,19 @@ ACTIVITYPUB_PROFILE = {
     "url": "https://diaspodon.fr/system/accounts/headers/000/033/155/original/45ae49a08ecc5f27.png?1537060098"
   }
 }
+
+ACTIVITYPUB_PROFILE_INVALID = {
+  "@context": [
+    "https://www.w3.org/ns/activitystreams",
+    "https://w3id.org/security/v1",
+  ],
+  "id": None,
+  "type": "Person",
+  "name": "Jason Robinson",
+  "url": "https://diaspodon.fr/@jaywink",
+  "publicKey": {
+    "id": "https://diaspodon.fr/users/jaywink#main-key",
+    "owner": "https://diaspodon.fr/users/jaywink",
+    "publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwVbaT5wvaZobfIB044ai\nhJg/XooEn2jSTnTY1K4mPmhdqYUmszpdXKp64OwA+f3SBuIUIkLAYUSB9Fu19zh+\nzOsoGI5gvA32DHY1vaqdKnT9gt3jKS5AdQ3bl0t9f4pPkO2I5YtQOWV1FvBcwPXG\nB0dIqj0fTqNK37FmyybrRD6uhjySddklN9gNsULTqYVDa0QSXVswTIW2jQudnNlp\nnEf3SfjlK9J8eKPF3hFK3PNXBTTZ4NydBSL3cVBinU0cFg8lUJOK8RI4qaetrVoQ\neKd7gCTSQ7RZh8kmkYmdlweb+ZtORT6Y5ZsotR8jwhAOFAqCt36B5+LX2UIw68Pk\nOwIDAQAB\n-----END PUBLIC KEY-----\n"
+  },
+}