John Donne's Grandfather Survives the Prebendaries Plot

Blessed Germain or Jermyn or German Gardiner was executed at Tyburn on March 7, 1544. He was beatified in 1886 by Pope Leo XIII. As Bishop of Winchester Stephen Gardiner's nephew and secretary, he became involved in the Prebendaries' Plot of 1543 and was hung, drawn, and quartered for the denial of Henry VIII's Supremacy over the Church of England.

The Prebendaries' Plot was named after the five prebendary canons of Canterbury Cathedral (including William Hadleigh, a monk at Christchurch Canterbury prior to the monastery's dissolution) who formed its core. Others involved were two holders of the new cathedral office of "six preacher" (created in 1541), along with various local non-cathedral priests and Kentish gentlemen (eg Thomas Moyle, Edward Thwaites and Cyriac Pettit). Simultaneous agitation at the court in Windsor, and the conspiracy in general, was led covertly by Stephen Gardiner, bishop of Winchester.

Henry VIII's chaplain Richard Cox was charged with investigating and suppressing it, and his success (240 priests and 60 laypeople of both sexes were accused of involvement) led to his being made Cranmer's chancellor (and later, under Elizabeth, bishop of Ely). Gardiner survived, though his relation Germain Gardiner, who had acted as his secretary and intermediary to the plotters in Kent, was executed in 1544 for questioning the Royal Supremacy.

So Blessed Germain Gardiner was left as the scapegoat to suffer for the plot, while Henry VIII, still valuing Bishop Stephen Gardiner's efforts in supporting both Henry's "Great Matter" and his more "conservative" reformation of the Church, spared his uncle.

Along with Gardiner, Blessed John Larke, friend of St. Thomas More and former rector of Chelsea (More's parish) and Blessed John Ireland, also connected with St. Thomas More and Chelsea, were executed for denying Henry VIII's Supremacy. Robert Singleton, a parish priest, was also executed under a charge of treason, but he has not been beatified.

John Heywood, the playwright and grandfather of John Donne was also on the scaffold at Tyburn sentenced to death, but he recanted and was spared. He also had connections to St. Thomas More and survived the ups and downs of the Tudor succession until Elizabeth I's reign. Then he went into exile in Mechelen, Belgium where he died around 1580. You may have used one of John Heywood epigrams and not realized the source: wikipedia lists many of the most famous:

What you have, hold.
Haste maketh waste. (1546)
Out of sight out of mind. (1542)
When the sun shineth, make hay. (1546)
Look ere ye leap. (1546)
Two heads are better than one. (1546)
Love me, love my dog. (1546)
Beggars should be no choosers. (1546)
All is well that ends well. (1546)
The fat is in the fire. (1546)
I know on which side my bread is buttered. (1546)
One good turn asketh another. (1546)
A penny for your thought. (1546)
Rome was not built in one day. (1546)
Better late than never. (1546)
An ill wind that bloweth no man to good. (1546)
The more the merrier. (1546)
You cannot see the wood for the trees. (1546)
This hitteth the nail on the head. (1546)
No man ought to look a given horse in the mouth. (1546)
Tread a woorme on the tayle and it must turne agayne. (1546)
Many hands make light work. (1546)
Wolde ye bothe eate your cake and haue your cake? (1562)
When he should get aught, each finger is a thumb. (1546)

His son Jasper Heywood, SJ was briefly in charge of the English mission, arrested and exiled. He is best known for his translations of Seneca.

John Donne's Uncle, Jesuit Jasper Heywood

Father Jasper Heywood died on January 9, 1598; he was a Jesuit missionary priest who had attended Oxford University and had been a fellow at both Merton College and All Souls College but had to leave during Elizabeth I's reign because he was Catholic. He went to Rome and studied for the priesthood and then became a Jesuit. According to the Catholic Encyclopedia:

After two years at the Roman College he was made professor of moral philosophy and controversy at the Jesuit College of Dillingen in Bavaria where he stayed for seventeen years. In 1570 he took the full Jesuit vows. In 1581 he came to England as a missionary with Father William Holt, and together they were the means of numerous conversions to the Catholic Faith. Father Heywood was appointed superior of the English Mission in succession to Father Parsons. In the controversy then rife concerning the observance by English Catholics of the severe ancient fasts, Heywood opposed the rigid party. He was considered by the authorities to have erred on the side of laxity, and was therefore recalled from England by his superiors. On this return journey he was arrested as a suspected priest, brought back to London and imprisoned. Several times he was examined by the Privy Council and strongly urged to conform, but neither bribes nor threats moved him, and he was brought up for trial at Westminster with other priests. Before the trial finished, however, he was taken to the Tower and closely imprisoned for seventeen months. Finally, he was exiled with others to the coast of France, and forbidden under pain of death to return. He then went to the Jesuit College at Dôle in Burgundy, and in 1589 was sent to Rome and afterwards to Naples, where, worn out by the sufferings and hardships he had undergone, he died at the age of sixty-three.

As a classical scholar he is known for his translations of three of Seneca's tragedies: the Troas  the Thyestes and Hercules Furens.

John Donne's mother Elizabeth was Jasper Heywood's sister--and their father was the famous poet, playwright, and epigrammist, John Heywood. The Heywood and Donne families were devout Catholics, but John Donne left the Catholic Church soon after his brother Henry died in prison after being tortured and betraying Blessed William Harrison, SJ, who was executed on February 18, 1594. John Donne would also go on to write anti-Jesuit works: Ignatius His Conclave and the Pseudo-Martyr. Dennis Flynn explored John Donne's Catholic connections, including to his uncle in John Donne & The Ancient Catholic Nobility.