David’s Great-great-grandfather was Lewis ap John (Wallis) who was Vicar of Abergavenny and Llandeilo Bertholau. Lewis ap John was Vicar of St Mary’s Priory Church where the tomb of his son, Dr David Lewis, can be seen today. Since Morgan Lewis had his son David brought up in the Established Church, David would have been baptised in the Priory Church where once his great-great-grandfather had been the vicar.
Lewis ap John’s grandson, David Baker, became a Benedictine. As Dom Augustine Baker, David Baker is famous as a mystic and writer. He was also instrumental in re-establishing the Benedictines in England. Dom Augustine Baker O S B was the great uncle of St David Lewis and the Benedictine and the future Jesuit Martyr would have met on the Benedictine’s last visit to Abergavenny in 1620. On his last visit to his hometown, Augustine Baker stayed with his sister, Margaret (Baker) Pritchard. Margaret Pritchard was the grandmother of St David Lewis.