Catherine was born on 9 May 1725 in Barsham, the oldest child and only daughter of the Reverend Maurice Shelton Suckling, the rector of Barsham and Woodton, and a prebendary of Westminster and his wife, Ann Mary Turner (1693–1768), daughter of Sir Charles Turner and Mary Ann Walpole (1673–1701).

[1] The marriage was a good one for Edmund, for Catherine was related through her father to the poet Sir John Suckling, and through her mother to the powerful Walpole family, by now elevated to the peerage as the Earls of Orford.

[4] Horatio was a sickly child, and Edmund feared he would not live long enough to be baptised at the public ceremony arranged for 15 November.

[4] The last of the Nelson children followed, Ann on 20 September 1760, Edmund on 4 June 1762, Suckling on 5 January 1764, and Catherine on 19 March 1767.

He had begun to call in favours with relatives to ensure that educations and positions could be found for them, and Suckling promised to do what he could for one of the boys, using the patronage available to him as a naval captain.