Sir John was born in 1577 to a Norfolk family with a colourful pedigree – the Heveninghams claimed to be descended from one of the men who guarded Christ’s tomb.  More realistically they originated from Suffolk.

Suffice it to say the Heveninghams did all the usual things associated with county gentry i.e. education (in this case Cambridge), study of the law, JP, sheriff and member of parliament.

In January 1627, John Heveningham was summoned to appear before the Privy Council for his failure to pay Charles I’s forced loan.  He was packed off to the Marshalsea.  Being a gentleman it was assumed that he wouldn’t skip town so was allowed, in July, to take himself back to Norfolk to put his affairs in order.  Having done that he was placed under house arrest in Shropshire before being moved back to London once again for a stint in the Fleet Prison.

It was from the Fleet that Heveningham petitioned the King’s Bench for a bill of habeas corpus which would have tested whether or not he was being legally detained.  The matter was not resolved legally on account of the fact that the bench had no desire to alienate the king but Heveningham and his four companions were released at the beginning of 1628.

Heveningham found that becoming a jailbird had done his “street cred” the world of good in Norfolk where the king’s forced loan was deeply resented.  He was returned to Parliament on a wave of popular support.

Heveningham died in 1633. He was succeeded by his son William who was returned to Parliament in 1640.  He served on the committee of the Eastern Association during the English Civil War so was in all respects a parliament man until it came to signing the death warrant of Charles I – which he refused to do in his capacity of commissioner to the high court. Despite this William did agree the execution of the king in his role as member of parliament which was sufficient to make him a regicide.

Having disposed of the king William took a back seat in the running of the country but did manage to acquire rather a lot of sequestrated estates during the Commonwealth period.  Unfortunately for Heveningham the monarchy was restored in 1660 and whilst many things were conveniently forgotten regicide was not.  Heveningham surrendered himself, was put on trial and found guilty of treason for his part in Charles I’s death.  The fact that he had not signed the death warrant itself, together with his wife’s determined petitioning saw him being packed off to Windsor Castle where he remained until he died in 1678.

If you want an interesting and unexpected historical fact then it must be that Sir John Heveningham was a trustee of the Paston estate – his wife Bridget was a Paston – as in the fifteenth century letters family- demonstrating the small pool of  landed families in each county that intermarried over the centuries to create a tight knit network or a smouldering keg of interfamilial feuding.

As for William Heveningham, he married in 1650 to Mary Carey the daughter of the Earl of Dover. The earl was John Carey, a son of Henry  Lord Hunsdon – the son of Mary Boleyn…and potentially Henry VIII.

https://www.historyofparliamentonline.org/volume/1604-1629/member/heveningham-sir-john-1577-1633