Complex sentence: Historical sources vary as to the correct spelling of M'Naghten's name: his signature supports a variety of hyothetical spellings, and in the manifold legal writings on the case, it is not uncommon to see McNaghten, M'Naughten, or some other variant.
Split into simpler sentences: Historical sources vary as to the correct spelling of M'Naghten's name. His signature supports a variety of hyothetical spellings, and in the manifold legal writings on the case, it is not uncommon to see McNaghten, M'Naughten, or some other variant.