Complex sentence: Adam left Oxford and practised his profession for seven years as an advocate in the archiepiscopal court of Canterbury, 1390--1397, sitting on the Parliament of 1397 and in 1399 accompanied the Archbishop and Bolingbroke's army on the march from Bristol to Chester.
Split into simpler sentences: Adam left Oxford and practised his profession for seven years as an advocate in the archiepiscopal court of Canterbury, 1390--1397, sitting on the Parliament of 1397. In 1399 he accompanied the Archbishop and Bolingbroke's army on the march from Bristol to Chester.