Complex sentence: The cultus of Sidwell has been active at Exeter from early times; pilgrims were visiting her shrine by 1000, and their activity is mentioned both by John Leland and William Worcestre.
Split into simpler sentences: The cultus of Sidwell has been active at Exeter from early times. Pilgrims were visiting her shrine by 1000, and their activity is mentioned both by John Leland and William Worcestre.