On 28 May 1554, when she was about eighteen years old, Mabel married the eldest brother of her stepmother, Gerald FitzGerald, 11th Earl of Kildare, known as The Wizard Earl, whom she had met at the court of King Edward VI. According to historian Mary Anne Everett Green in her Royal and Illustrious Ladies, the pair actually met at a masked ball and Mabel immediately fell in love with him. FitzGerald was given his sobriquet on account of his interest in alchemy. They were married in the Chapel Royal during the reign of Queen Mary I, who held the Browne family in high esteem. Mabel was a gentlewoman of Queen Mary's Privy Chamber, and in February, the same year of his marriage to Mabel, FitzGerald had helped suppress the rebellion of Sir Thomas Wyatt. Mabel went to live with her husband at Kilkea Castle, Kildare, in Ireland, the country where she was to spend most of her life. Together FitzGerald and Mabel had five children.
Lord Gerald FitzGerald, Lord Offaly, Lord Garratt, married in October 1578, Catherine Knollys, a granddaughter of Mary Boleyn. They had a daughter Lettice who married Sir Robert Digby. These were the direct ancestors of the celebrated 19th-century adventuress Jane Digby.
Lord Henry Na Tuagh FitzGerald, 12th Earl of Kildare,, married Lady Frances Howard, by whom he had female issue.
Lady Mary FitzGerald, married Christopher Nugent, 14th Baron Delvin, by whom she had issue.
Recusant leanings
While Mabel had enjoyed the favour of Queen Mary, she was less welcome at the court of the latter's successor, Queen Elizabeth I, as Mabel's recusant leanings were well known. She kept a number of priests in her household, including her private chaplain Nicholas Eustace, who was related to the Catholic rebel James Eustace, 3rd Viscount Baltinglass, and she hired the suspected Father Compton to serve as the tutor of her children. She was also a close friend of Jane Dormer, Duchess of Feria, their friendship dating from the time when they had both served in the household of Queen Mary. According to author Vincent P. Carey, Mabel "maintained a refuge and library for the Jesuit missionary Robert Rochfort. Despite her overt Roman Catholicism, Mabel was never accused of treason against Queen Elizabeth, unlike her husband who fell under increasing suspicion of disloyalty in his later years and spent several years in the Tower of London. Elizabeth however had a certain fondness for him and refused to take any decisive action against him. He died in London in 1585, technically a free man, though he was forbidden to leave the city.
Death
Mabel died in Ireland on 25 August 1610. She was about seventy-four years of age. Her last years were troubled by a lawsuit brought against her by her granddaughter Lettice Digby, alleging that Mabel had fraudulently tampered with her husband's will. Mabel admitted that the will had been altered but insisted that this had been done on legal advice.
In fiction
Mabel Browne is a minor character in Anya Seton's historical romance Green Darkness, where her brother Viscount Montagu, his wife Magdalen Dacre, and Cowdray Castle are featured prominently.