Board Thread:Theories and Speculation/@comment-32369776-20170708034118/@comment-734582-20170711084810

UltimaDude wrote: Therefore, the split must've happen much later, but before the founding of Konoha and the shinobi system I don't think this is necessarily true. It appears that the Senju and Uchiha simply were the guardians of their forefather's ideology (will of fire versus Uchiha's might makes right) in addition to their genes. The Uzumaki appear to be genetically and ideologically related but not part of that very core group.

Though to be clear, i don't think the clans formed immediately after Asura's and Indra's demise. But somewhere within that century or so, it appears their followers formed these clans.