 Robert Catesby was the third and only surviving son of Sir William and Anne (née Throckmorton) Catesby, and was probably born in or after 1572 at his father's main residence in Lapworth. Robert was a lineal descendant of Sir William Catesby (1450 – 1485), the influential councillor of Richard III captured at the Battle of Bosworth and executed. On his mother's side he was descended from Sir Robert Throckmorton of Coughton, and his second wife, Elizabeth Hussey. His parents were prominent recusant Catholics; his father had suffered years of imprisonment for his faith, and in 1581 had been tried in Star Chamber alongside William Vaux, 3rd Baron Vaux of Harrowden, and his brother-in-law Sir Thomas Tresham, for harbouring the Jesuit Edmund Campion. The head of the Throckmortons, Sir Thomas Throckmorton, was also fined for his recusancy, and spent years in prison. Another relation, Sir Francis Throckmorton, had been executed in 1584 for his involvement in a plot to free Mary, Queen of Scots.
