Complex sentence: When considering candidates for this important position, the Puritans had at first hoped to engage Captain John Smith, one of the founders of the English colony at Jamestown, Virginia who had also explored and mapped the North American coast.
Split into simpler sentences: When considering candidates for this important position, the Puritans had at first hoped to engage Captain John Smith. As one of the founders of the English colony at Jamestown, Virginia, Smith had explored and mapped the North American coast.