The Catholic University of Leuven, founded in 1425 by Pope Martin V, which makes it the oldest Catholic university still active. In its early days this university was modeled after the universities of Paris, Cologne and Vienna.

The first library was located in the university halls, and was enlarged in 1725 in baroque style. In 1914, during World War I, Leuven was plundered by German troops, and a large part of the city was put to fire, effectively destroying about half of the city. The library was lost, as well as about 300,000 books, and a huge collection of manuscripts collected since the university's founding in 1425.

The new main library was built between 1921 and 1928 and designed by the American architect Whitney Warren in low countries neorenaissance style. Its monumentality is a reflection of the victory against Prussian Germany. It is one of the largest university buildings in the city. However, in 1940, ironically, during the German armed forces invasion of Leuven, the building largely burnt down, including its (at that time) 900,000 manuscripts and books.

The university split in 1968 due to Flemish claims of discrimination to form two universities:

• Katholieke Universiteit Leuven, Leuven, Belgium, Dutch-speaking, which lies in Leuven
  • KULAK, Katholieke Universiteit Leuven, Afdeling Kortrijk, its branch campus in Kortrijk
• Université catholique de Louvain, Louvain-la-Neuve, Belgium, French-speaking

Notable alumni

• Adriaan Florisz. Boeyens (1459 - 1523), later Pope Adrian VI.
• Desiderius Erasmus (1466 - 1536), humanist.
• Gerard Mercator (1512 - 1594), cartographer
• Andreas Vesalius (1514 - 1564), father of modern anatomy.
• Rembert Dodoens (1517 - 1585), botanist.
• Justus Lipsius (1547 - 1606), humanist.
• Cornelius Otto Jansen (1585 - 1638), father of the Jansenist movement.
• Charles Nerinckx (1761-1824), founder of Sisters of Loretto.
• Georges Lemaître (1894 - 1966), astronomer and proposer of the Big Bang theory.
• Otto von Habsburg (1912 - ), the current head of the Habsburg family.
• Malachi Martin (1921 - 1999), Irish writer
• Charles Jean de la Vallée-Poussin, a mathematician who proved the prime number theorem
• Georges Lemaître, who proposed the Big Bang theory (at the time, Université catholique de Louvain was based in Leuven and was the same as the Katholieke Universiteit Leuven)
• Christian de Duve, Nobel Prize in Medicine 1974, for his discoveries concerning the structural and functional organization of the cell
• Geza Vermes, religious historian and translator into English of the Dead Sea Scrolls
• Camilo Torres Restrepo, colombian priest and guerillero.
• Gustavo Gutierrez, peruvian dominican and theologian, founder of the Liberation Theology
• Abdul Qadeer Khan, founder of Pakistan's nuclear weapons development programme

Roman Catholic universities and colleges in Belgium | Pontifical Universities | 1425 establishments | Educational institutions established in the 15th century | Universities in Belgium

Katholische Universität Löwen | אוניברסיטת לובן