Lady Mary Charlotte Anne Wellesley (d.1845), who married Right Hon. Sir Charles Bagot, Bart., G.C.B., on 22 July 1806. The couple had three sons and five daughters.[5]
In 1789, Wesley-Pole changed the spelling of his surname to Wellesley-Pole, in keeping with the practice of other family members.[8] In 1821, he became Baron Maryborough, and his wife became Lady Maryborough. In 1842, when he inherited the earldom of Mornington from his older brother, Richard Wellesley, Katherine became Countess of Mornington.
Following the earl's death in 1845, the earldom passed to their eldest son. The countess died at her London home in Grosvenor Square, and was buried with her husband and other members of the family at Grosvenor Chapel.
A watercolour portrait of the countess, by William Wood, was given by her to her daughter in 1844.[9]
^The Register of Births & Baptisms in the Parish of St James in the County of Middlesex Vol. V. 1761-1786. 15 February 1761.
^Christie's: Lotnotes by a drawing of the Wellesley-Pole sisters, by Thomas Lawrence. Url visited on 21 March 2012
^G.E. Cokayne; with Vicary Gibbs, H.A. Doubleday, Geoffrey H. White, Duncan Warrand and Lord Howard de Walden, editors, The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, Extant, Extinct or Dormant, new ed., 13 volumes in 14 (1910-1959; reprint in 6 volumes, Gloucester, U.K.: Alan Sutton Publishing, 2000), volume IX, pages 239-240