Born on 22 June 1872 at Todmorden, the sixth son of the Rev. Rennell Francis Wynn Molesworth, rector of Washington, Co Durham, and his second wife Frances Elizabeth, daughter of Admiral George Henderson, he was descended from Robert, first Viscount Molesworth (1656-1725), ambassador and politician.

Born at Wigan on 10 December 1870 eldest son of John Pendlebury a clothing manufacturer of Standish, Lancashire, he was educated at St John's College, Grimsargh near Preston, and at Pembroke College, Cambridge, where he was exhibitioner, prizeman and University scholar, and took first-class honours