Blessed Thomas Thwing (1635–1680) was an English Roman Catholic priest and martyr, executed for his supposed part in the Barnbow Plot, an offshoot of the fabricated popish plot invented by Titus Oates. His feast day is October 23.
His father was George Thwing, Esq. of Kilton Castle, Brotton, and Heworth Hall. His mother was Anne, daughter of Sir John Gascoigne and his wife Anne Ingleby, and sister of Sir Thomas Gascoigne, 2nd Baronet, of Barnbow Hall, Barwick in Elmet. Both parents were Yorkshire recusants. Thomas was born at Heworth Hall, Heworth, York, and educated at St Omer and at the English College (Douai), ordained a priest and sent to minister at the English Mission in 1665, which he did for roughly 14 years. Until April 1668, he was chaplain at Carlton Hall, the seat of his cousins, the Stapleton family. He opened a school at Quousque, the Stapletons' dower-house. In 1677 Mary Ward's Institute of the Blessed Virgin Mary (IBVM) began its foundation in the house given to the order by Thomas' maternal uncle, Thomas Gascoigne, at Dolebank, where three of Father Thwing's sisters were members. Thwing became chaplain and it was there that he was arrested in early 1679.
At the time of the Titus Oates scare, or "Popish Plot", two servants, Bolron and Mowbray, who had been discharged from Sir Thomas Gascoigne's service for dishonesty, sought vengeance and reward by revealing a supposed plot by Gascoigne and others to murder King Charles II. At first the informers made no mention of Thwing. Nevertheless, Gascoigne, his daughter Lady Tempest, Thwing, and others were arrested on the night of 7 July 1679, and removed to London for trial at Newgate.
Gascoigne sensibly demanded to be tried by a Yorkshire jury, whom the judges admitted were better equipped to decide on the credibility of witnesses, most of whom they knew personally, than were the judges themselves. The trial was postponed to the summer assizes. Thwing was brought to the bar on 29 July, and Gascoigne's former servant, Robert Bolron, testified against him. All of the accused were acquitted except Thwing, who was brought back to York, where he was arraigned at York on 17 March 1680, along with, among others, a kinsman, Sir Miles Stapleton. The prosecution played upon a list of Catholics which had been found on the night of the arrest. In reality they were not conspirators but supporters of the new convent at Dolebank which Gascoigne's daughter Lady Tempest had recently founded. At her father's trial the Court had heard much evidence about the convent, but the judges apparently did not regard her actions as treasonable, since at her own trial she was acquitted. Sir Miles Stapleton was also acquitted, as was another alleged conspirator, Mary Pressicks: the judges, showing far more impartiality than in earlier Popish Plot trials, ruled that her statement that "we shall never be at peace till we are all of the Roman Catholic faith" was not treasonable, but a simple expression of opinion.