Ambrose Lisle March Phillipps de Lisle (17 March 1809 – 5 March 1878) was an English Catholic convert. He founded Mount St. Bernard Abbey, a Trappist abbey in Leicestershire and worked for the reconversion or reconciliation of Britain to Catholicism.
He was the son of Charles March-Phillipps of Garendon Hall, Leicestershire, and Harriet Ducarel, a lady of Huguenot descent. The de Lisle family of Leicestershire were originally the Phillippses from London. The Garendon estate near Loughborough, was inherited by Thomas March, who adopted the name Phillipps, and married Susan de Lisles. Their son, Charles, adopted the de Lisle crest and arms. Steady accumulation of landed property made him one of the ‘wealthiest commoners’ in England. When Charles March-Phillipps died in 1862, Ambrose took the additional name of Lisle, becoming Ambrose Charles Lisle March Phillipps de Lisle.
He spent his earliest years at his birthplace and was brought up as a member of the Church of England, receiving his first religious instruction from his uncle, William March Phillipps, a High Church clergyman. In 1818 Ambrose was sent to a private school in South Croxton, whence he was removed in 1820 to Maizemore Court School, near Gloucester, kept by the Rev. George Hodson. The Bishop of Gloucester, having married Sophia March Phillipps, was his uncle by marriage, and so the boy spent Sundays and holidays at the bishop's palace.
At school he met for the first time a Catholic, the Abbé Giraud, a French émigré priest. A visit to Paris in 1823 gave him his first acquaintance with Catholic liturgy. The effect on his mind was shown on his return home when he persuaded the Anglican rector to place a cross on the communion table, but this first effort to restore the cross to English churches was stopped by the Bishop of Peterborough. He converted to Catholicism, and immediately removed from Mr. Hodson's school, and returned home with his father, who arranged for him to continue his preparation for the university under the private tuition of the Rev. William Wilkinson. He was obliged every Sunday to attend the Anglican church, but did not join in the service.