From the Jesuit Curia in Rome, this biography of today's martyr:
Little is known about Father Nelson's ministry except that it lasted only one year before he was arrested on the evening of Dec. 1, 1577 when priest-catchers burst into his residence as he was reading his breviary. They arrested him on suspicion of being a Catholic; but when he was brought before the queen's high commissioners and asked who the head of the Church was, he boldly answered that it was the pope, thus sealing his fate. His trial took place February 1 and featured the comments he made before the commissioners; since he refused to take the oath acknowledging the queen's supremacy in religious matters, he was found guilty of high treason and condemned to be executed as a traitor. Nelson had admired the Jesuits but their mission to England did not begin until two years after his death. He wrote to the French Jesuits asking to be admitted, and they were pleased to accept a priest about to be martyred. He was kept in a foul dungeon for two days and then dragged to Tyburn to be executed. As he gave his final words to onlookers, he was hanged but then cut down while he was still alive and disembowelled. He was beheaded and quartered with his body parts exhibited on London Bridge and the city gates as a warning.
This Jesuit website gives some details about his last words:
Blessed John Nelson could definitely be a patron of those who enter the religious life or the priesthood when they are older than the norm. He was beatified by Pope Leo XIII in 1886.