This is what the SicyonianCleisthenes had done, and the Athenian Cleisthenes, following the lead of his grandfather and namesake, decided out of contempt, I imagine, for the Ionians, that his tribes should not be the same as theirs.

When he had drawn into his own party the Athenian people, which was then debarred from all rights, he gave the tribes new names and increased their number, making ten tribe-wardens in place of four, and assigning ten districts to each tribe. When he had won over the people, he was stronger by far than the rival faction.