In memory of his parents, Sir John erected a pair of almost life-size monumental brasses in St Decuman's Church, Watchet, and also erected an almost identical pair (considered the finest of their style in England), also set into Purbeck marble, in memory of his uncle Nicholas Wadham and his wife on their chest tomb in the Wadham Chapel in the Church of St Mary, Ilminster.
[10] That night a "covetous sexton" crept into the church and in attempting to remove a valuable ring, cut the lady's finger, thereby awakening her from a cataleptic trance.
He was a minor aged twelve at the death of his father and as a tenant-in-chief his wardship and marriage reverted to the crown, Queen Elizabeth I, to be granted to whom she pleased.
He played an important role in the defence organisation of Somerset, the substantial growth of which is shown by the muster in 1580 being 12,000 able footmen, double the total twenty years earlier.
While the defeat of the Spanish Armada saved England from the feared invasion, the significance and value of the defence movement was in keying up the nation and teaching it to realise the heritage it had to defend.
A detailed record, preserved in the College archives, was drawn up by Wyndham of a discussion held with his uncle four days before his death in 1609 as follows: In 1599 he succeeded to the Felbrigg estate in Norfolk, including Felbrigg Hall, from his father's first cousin Thomas Wyndham (d. 1599), who like his two brothers Sir Roger and Francis (d. 1592), Judge of Common Pleas (whose monument exists in St Peter Mancroft in Norwich) died without issue.
[16] Sir John gave Felbrigg to his third son Thomas Wyndham (d. 1653), for whom he rebuilt the manor house, completed in 1624,[17] which survives today.