diff --git a/tiddl/models/resource.py b/tiddl/models/resource.py
index 16cb97e..5131aff 100644
--- a/tiddl/models/resource.py
+++ b/tiddl/models/resource.py
@@ -121,7 +121,7 @@ class Album(BaseModel):
     numberOfVideos: int
     numberOfVolumes: int
     releaseDate: str
-    copyright: str
+    copyright: Optional[str] = None
     type: str
     version: Optional[str] = None
     url: str