Lord Deputy of Ireland He was known as a rash, angry and temperamental man, skilfull in naval and military affairs. Philip served during the Spanish War. He was with the Black Prince at a famous victory at Battle of Najera. He was knighted after the battle with brother Peter, and his cousin Hugh and was knighted by Edward the Black Prince, along with his brothers Hugh and Peter, in Spain the day before the Battle of Najera. In February 1383, he become Lord Lieutenant of Ireland, serving for 10 years under King Richard II. He attended the parliament that met at Salisbury in April 1384, but in July his duties were taken over by the deputies. In 1385 the King gave him powers of administration in Dublin. He also served as Steward of Cornwall in the 12th year of the reign of Richard II. By 1399 Sir Philip was an experienced soldier called upon to suppress the welsh revolt. He called up the commissions of array. He bought transporters of the soldiers and horses for the 1402 expedition to Brittany, and the sailing against the King of Scotland in 1400. Sir Philip was imprisoned in the Tower in November 1402 for clerical abuses against the Church. On 29 November he was forced to pay a recognizance of £100 by Sir John Arundell and to Sir John Herle and Sir William Sturmy a surety of £1000. Philip was granted Powderham Castle by his mother upon her death in 1391 and seven other manors. He was succeeded by his son, Richard, Lord Bishop of Ireland, upon his death on 29 July 1406. At that time he held one manor and hamlet in Dorset; three manors and a moiety and three advoswons in Somerset; and seventeen manors and five advowsons in Devon with some smaller properties. He was valued in 1405 to have an income of £140 pa. Gibbs, Roscoe; Halliday, Maria, A delineation of the Courtenay mantelpiece in the episcopal palace at Exeter, by R. Gibbs, with a biogr. notice of P. Courtenay, Bishop of Exeter 1478 to 1487, to which is added a description of the Courtenay mantelpiece, by M. Halliday, Oxford University, pp. 2, Vivian, John Lambrick, The visitations of Cornwall: comprising the Heralds' visitations of 1530, 1573 & 1620, W. Pollard, pp. 102–103,
C Rawcliffe, "Parliament and Settlement of disputes", Parliamentary History, ix, pt 2, 334-7