The oldest university in Ireland, Trinity College Dublin, has long been at the heart of Dublin's history. The first University of Dublin was established in 1320 in connection with Saint Patrick's Cathedral but lacked an endowment and functioned poorly, finally closing with the dissolution, by Henry VIII, of the cathedral foundation.

Also known as Dublin University, Trinity was founded in 1591, by Elizabeth I as the "mother of an university" with the title of the "College of the Holy and Undivided Trinity, near Dublin."

The library at Trinity houses a notable collection of old Irish illuminated manuscripts, including the Gospels transcribed in the 7th-century Book of Durrow and the unique 8th-century Book of Kells. Since 1801 the college has been entitled by law to receive a copy of every book published in Great Britain and Ireland. Among former students of the university were the Irish philosopher George Berkeley, the English satirist Jonathan Swift, the British statesman Edmund Burke, and the Anglo-Irish playwright Oliver Goldsmith.

Trinity College continues to be a popular tourist attraction as well as an educational institution for almost 10,000 students.
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