William Petre, 2nd Baron Petre (24 June 1575 – 5 May 1637) was an English peer and Member of Parliament.
He was born the son of Sir John Petre, 1st Baron Petre and was educated at Exeter College, Oxford and the Middle Temple.
He was elected MP for Essex in 1597, knighted in 1603 and inherited the Barony and the Ingatestone estate on his father's death in 1613. In 1623 he was appointed justice of the peace for Essex but, due to his uncompromising recusancy, he was dismissed in 1625 from the Magistracy and deprived of all of his other public offices.
From its position on the Harwich road, and proximity to London, Ingatestone Hall was a constant meeting place and refuge for those disaffected to the Protestant religion or to the reigning sovereign. For example:
13th July 1627. My Lord Petre’s son going over sea to Flanders with many letters, and two barrels of treasure, gold and silver, in a pink, is brought back and committed, and here it is said, that at his father’s house at Ingatestone in Essex divers great Papists had been in consultation about a fortnight and departed thence but on Saturday last.
Secret guests may often have used the hiding place discovered at the Hall in 1855. It is very probable that some of the inns had similar places of concealment for these visitors, whom it would not always be safe to hide the Hall, for example the attic in the White Hart, the huge chimney block of the Eagle, behind the present billiard room, the present great cupboards of the Crown. Many of the houses about Fryerning Hall by the old chimneystacks, and for example Furze Hall might reveal similar ones if thoroughly explored.
It does not appear that the 2nd Baron got into any serious trouble about the Papists who frequented Ingatestone, in part due to the support of King Charles I. Possibly, by this time the Hall was used as a dower house, or a residence for the sons, as the 3rd Baron is described in 1638 by William Riley, Blue Mantle, as dying at West Thorndon, and being buried in an old vault appropriated to his family in the chancel of the Parish Church of Ingatestone.
William, 2nd Baron, died in May 1637, and is buried in the same vault. The tomb, which he erected in the north chapel in memory of his parents, bears also, his own effigy and that of his wife and children, but the tablet over his head is still waiting for an inscription.