Complex sentence: Congregationalism is not limited only to organization of Christian congregations; the principles of congregationalism have been inherited by the Unitarian Universalist Association, some of which are Christian assemblies, by direct historical descent from the Congregational Church.
Split into simpler sentences: Congregationalism is not limited only to organization of Christian congregations. The principles of congregationalism have been inherited by the Unitarian Universalist Association, some of which are Christian assemblies, by direct historical descent from the Congregational Church.