Background
He was born in Kinvara, County Galway, the second son of Richard Óge Martyn (died 1648) of Dunguaire Castle and his wife Magdalen French. His father was a wealthy landowner, lawyer and politician, who with his cousin Patrick D."Arcy belonged to a group of Roman Catholic lawyers in County Galway who continued to practice law in the 1630s, in defiance of the Penal Laws, which barred Catholics from the practice of any profession, until the Crown finally put a stop to their practice. Later Richard was a key figure in Confederate Ireland.
Career
He was one of the Roman Catholic judges appointed to the Irish Bench by King James II, as part of his overall policy of creating an exclusively Catholic Irish administration. After the downfall of James" cause at the Battle of the Boyne he was accused of attempting to ingratiate himself with the new regime, but soon afterwards he was attainted, fled the country and died in exile. Peter entered Middle Temple in 1663 and the King"s Inn in 1673, and was on the Connaught Circuit in 1683.
He became wealthy, and bought the manor of Kilconnel.
Ball points out that Martyn had only 14 years in practice. On the other hand his wealth and social standing may have made him an acceptable candidate for judicial office.
He was appointed third justice of the Court of Common Pleas (Ireland). He went regularly on the Connaught circuit as judge of assize.
With his family he fled the country and died in exile.
His precise date of death is unknown. Burke, writing in 1885, described Martyn as a "great humourist" of whom many stories were still told, but apparently he did not think any of the stories memorable enough to repeat.
