diff --git a/sphinx/domains/c.py b/sphinx/domains/c/__init__.py
similarity index 100%
rename from sphinx/domains/c.py
rename to sphinx/domains/c/__init__.py
diff --git a/sphinx/domains/cpp.py b/sphinx/domains/cpp/__init__.py
similarity index 100%
rename from sphinx/domains/cpp.py
rename to sphinx/domains/cpp/__init__.py
diff --git a/sphinx/domains/python.py b/sphinx/domains/python/__init__.py
similarity index 100%
rename from sphinx/domains/python.py
rename to sphinx/domains/python/__init__.py
diff --git a/sphinx/domains/std.py b/sphinx/domains/std/__init__.py
similarity index 100%
rename from sphinx/domains/std.py
rename to sphinx/domains/std/__init__.py