Complex sentence: William Dyer was the messenger who returned to Rhode Island the following February, bringing the news of the return of the colony to the Williams' Patent of 1643, but Mary would remain in England for the next four years.
Split into simpler sentences: William Dyer was the messenger who returned to Rhode Island the following February, bringing the news of the return of the colony to the Williams' Patent of 1643. Mary, however, would remain in England for the next four years.