Complex sentence: He was a teacher in Dorchester, Massachusetts until 1695, when he led a group of his parishoners to the Ashley River in South Carolina to found the town of Dorchester, South Carolina, where he became pastor.
Split into simpler sentences: He was a teacher in Dorchester, Massachusetts until 1695. In 1695, he led a group of his parishoners to the Ashley River in South Carolina to found the town of Dorchester, South Carolina, where he became pastor.