Complex sentence: Purchas was born at Thaxted, Essex, and graduated at St John's College, Cambridge, in 1600; later he became a B.D., and with this degree was admitted at Oxford in 1615.
Split into simpler sentences: Purchas was born at Thaxted, Essex, and graduated at St John's College, Cambridge, in 1600. He held a Bachelor of Divinity degree, and with this degree was admitted at Oxford in 1615.