John Murray was the son of Mary Prior and the Rev. Thomas Murray. John Murray inherited his cousin's Tom Prior's estate on the condition that he added Prior to his surname.
John Murray/Murray Prior's first wife Mary was the daughter of Colonel O’Neil of County Down. Sources differ as to whether John and Mary had any surviving children. In the following, I follow Burke's Landed Gentry which states they had two sons: 1. Andrew Murray/Murray Prior, and 2. John Murray/Murray Prior.
After Mary's death, John Murray Prior married a second time, Jane, widow of the Rev. James Myhill and daughter of John Flood of Flood Hall, Kilkenny. Depending on the source, they had two or four sons (and perhaps daughters too though, like mothers, they are rarely deemed worthy of mention in the older genealogical sources and, with name changes on marriage, are harder to track). Source: John & John B. Burke, A Genealogical and Heraldic Dictionary of the Landed Gentry of Great Britain & Ireland: M to Z, London: Henry Colburn Publisher, 1846, p.1075. Other sources (e.g. Family Bible; Robert M-P, The Blood Royal of the Murray-Priors, ms written 1901-05 NLA Nq929.2M984) appear to have taken their information from Burke.