John de Courcy Ireland was an Irish

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 maritime historian

Maritime history

Maritime history is the study of human activity at sea. It covers a broad thematic element of history that often uses a global approach, although national and regional histories remain predominant...

 and political activist.
Born in Lucknow

Lucknow

Lucknow is the capital city of Uttar Pradesh in India. Lucknow is the administrative headquarters of Lucknow District and Lucknow Division....

, India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, where his County Kildare

County Kildare

County Kildare is a county in Ireland. It is part of the Mid-East Region and is also located in the province of Leinster. It is named after the town of Kildare. Kildare County Council is the local authority for the county...

 native father served in the British Army

British Army

The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

, he was educated at Marlborough College

Marlborough College

Marlborough College is a British co-educational independent school for day and boarding pupils, located in Marlborough, Wiltshire.Founded in 1843 for the education of the sons of Church of England clergy, the school now accepts both boys and girls of all beliefs. Currently there are just over 800...

, Oxford University and Trinity College Dublin, where he was awarded a PhD in 1951. The title of his thesis was "The Influence of the Sea on Civilisation".

In 1949 he taught at St Patrick's Cathedral School in Dublin and the next year received his doctorate on the sea in education from Trinity College Dublin.