The three cities were collectively called Sankatsu (three ports) during the Keicho era (although Kyo was not a port town but an inland city, due to its importance as a commercial and distributing center, this term was applied), however, in due course, the term Santo came to be used as well with the increased political presence of Edo.
三都は慶長年間には三ヶ津（さんかつ）と呼ばれていた（京は内陸都市で港町ではないが、物流拠点としての意味合いで用いられた）が、江戸の政治的地位の向上に伴い、三都の呼び名も用いられるようになった。