The Olde Mayor is the Mayor of Colonial-era Dimmsdale, known at the time as Ye Olde Town With No Name.
This Mayor looks and speaks very much similar to his modern day counterpart, the Mayor of Dimmsdale, with some minor differences in his clothing. He is the Mayor of Ye Olde Town With No Name, which would eventually become known as Dimmsdale.
He looks exactly like the modern day Mayor, except he wears the same Pilgrim hat and buckle belt as everyone else in the town.
He only appeared in the episode, "Which Witch Is Which?", where he was in charge of a naming ceremony for Ye Olde Town With No Name. He was initially going to name it Bitterburg, after the town's famous witch hunter Alden Bitterroot, but when Timmy Turner exposed Bitterroot as a witch himself, and when Bitterroot was sent down a well by Dale Dimm, the Mayor decided to name the city after Dale instead, giving it the name "Dimmsdale".