Michael Griffiths was born in London on 4th December 1928 and attended a prep school in Brighton and then moved north to attend the Ampleforth Preparatory School at Gilling Castle in North Yorkshire and from there he moved to Ampleforth School for his secondary education.
In 1946 he won a place at Balliol College in Oxford where he obtained a First Class BSc Honours Degree in Natural Sciences, majoring in Chemistry. Seven years later he obtained his MA.
On 24th September 1950, after completing his studies at Oxfoed, he joined the Benedictine Community at Ampleforth Abbey and was given the religious name Ambrose (after the saint who was Bishop of Milan in the fourth century.)
He was sent to the Benedictine House of Sant' Anselmo in Rome where he studied Theology and was ordained priest on 21st July 1957.
He taught Science, RE and woodwork at Ampleforth from 1958-1972, and became Head of the Science Department at the School.
From 1963-1971 he also taught Dogmatic Theology to the young monks of the community.
In 1972 he was appointed Procurator (Bursar) of the Abbey and was responsible for the day to day running, and the financial matters of the Abbey.
In 1976 he was elected Abbot of the Abbey by the Community and was in charge of Ampleforth for eight years until he was appointed as parish priest of St Mary's Parish in Leyland, Lancashire. As parish priest he was involved in the usual day to day activities and societies of normal parish life. After finishing his term as Abbot he was appointed as Titular Abbot of Westminster.
On 11th January 1992, Pope John Paul II announced that he had appointed the Rt Reverend Ambrose Griffiths OSB as the 11th Bishop of Hexham and Newcastle to succeed the Rt Rev Hugh Lindsay who had tendered his resignation as Bishop of the Diocese on the grounds of ill health.
On 20th March 1992, Ambrose was Ordained as Bishop by the Archbishop of Liverpool, Most Reverend Derek Worlock, in St Mary's Cathedral, Newcastle upon Tyne.
Bishop Ambrose tendered his resignation at the age of 75 to Pope John Paul II, a requirement necessary for all bishops. He was succeeded by Bishop Kevin Dunn (d 2008).
Bishop Ambrose Griffiths died peacefully on Tuesday 14 June 2011 aged 82.