Life and family
A Unitarian, he was born into the renowned Martineau family of Norwich and christened in the Octagon Chapel. His eldest brother Philip Meadows Martineau became a distinguished surgeon and his youngest brother Thomas fathered sociologist Harriet Martineau and religious philosopher James Martineau. Engineer John Martineau was another of Peter's nephews.
His first wife Susannah Scott had one son and his second marriage to Catherine Marsh brought him five more children, of whom Peter Martineau Jr was the oldest and Catherine Jr their first daughter – she married solicitor Edward Foss. Peter Jr wed Eliza Barnard and then Mary Anne, the sister of his schoolmate Sir Francis Ronalds. Peter Jr and Mary Anne's children included Sarah, whose husband was brewer and benefactor Charles Edward Flower. Peter and Catherine were buried at West Norwood Cemetery.