The youngest daughter of the brewer Henry Thrale and his wife Hester Thrale [Piozzi]; in 1795 she eloped with John Meredith Mostyn (1775-1807) from whom she later separated.

CORRESPONDENCE OF Cecilia Mostyn [née Thrale]:

Cecilia Thrale Mostyn to Lady Morgan, [June? 1856] in Lady Morgan’s Memoirs: Autobiography, Diaries and Correspondence. Second Edition, Revised 2 vols (London: Wm. H. Allen & Co., 1863)