Career
He was a distant cousin of Ranulph de Glanvill (d1191), Chief Justiciar of England during the reign of King Henry II (1154-1189), author of Tractatus de Legibus et Consuetudinibus Regni Angliae ("Treatise on the Laws and Customs of the Kingdom of England"), the earliest treatise on the laws of England. Born in Tavistock, he began as an attorney but joined Lincoln"s Inn in 1567 and was called to the bar in 1574: his practice proved lucrative and he amassed a considerable fortune, building a mansion at Kilworthy near Tavistock. He became a serjeant-at-law in 1589, and was both Lent and Autumn Reader of his Inn in that same year.
He sat as Member of Parliament for Launceston in the Parliament of 1584-1585, for Tavistock in 1586-1587 and Street Germans in 1593.
He was appointed Judge of Common Pleas in 1598. While riding on circuit, Sir John was killed when he fell off his horse, breaking his neck, on 27 July 1600.
He was buried in Tavistock Church. His memorial is considered to be one of the finest church monuments in the West of England dating from the 17th century.