About Katherine Porter
Year of birth, 1750, is from http://www.pastellists.com/Sitters.htm: Mrs Moses PORTER, née Kitty Lockman (c.1750-1788): S. Cotes.
The original record of the marriage in 1771 of Katherine Lockman and Rev Moses Porter at Clapham can be viewed on Ancestry. Moses is described as a parish clerk and batchelor. Katherine is a spinster of the Parish of St Giles in the Fields, Middlesex. Witnesses were Ann Oakes and Arabella Lockman.
The date of her death, 10 Dec 1788, and the place of her burial in Bath, are from 'The Genealogy of the Worcester Streets' [online at Ancestry.co.uk]. Moses died within 3 years, in 1791, and the children were looked after by Kitty's unmarried sister Arabella.
From: 'Clapham', The Environs of London: volume 1: County of Surrey (1792), pp. 159-169. URL: http://www.british-history.ac.uk/report.aspx?compid=45376 Date accessed: 19 June 2011: "On the outside of the south wall of the aisle, are tablets to the memory of John Lewis, Esq. commander of the Valentine East Indiaman, who died in 1790; and of Katherine, the wife of the Rev. Moses Porter, the late lecturer, who died in 1788."
Katherine Porter's Timeline
August 18, 1779
December 10, 1788