The Valletta Campus, popularly known also as the 'Old University Building' in Valletta, was constructed to serve as a Jesuit College, the first stone laid in 1595 by Grand Master Martino Garzes. Within two years the construction had advanced so much that it was possible to transfer to the new premises the classes which used to take place in an old house in Valletta.

Huddled between St. Paul, St Christopher, Merchants and Archbishop streets, the plan of the structure is typical of Renaissance large public buildings, with a central courtyard. Almost half of the site is taken up by the Jesuit church, whose construction started in 1592 and concluded in 1609.

The main entrance was initially from Merchants Street. Originally the facade was rather plain, with practically no decoration whatsoever. A Baroque facade was then re-designed in c. 1647 by famous architect Francesco Buonamici.

The ceiling of the corridors is a spectacle, lending itself to particular events such as Renaissance or Medieval themed dinners. Of equal interest is the wide staircase leading to the first floor, hardstone polished by the hundreds of Jesuit fathers, students and professors who made use of this building throughout the centuries. The portraits of distinguished personalities which embellish the corridors on the 1st floor were donated by Sir Joseph Nicholas Zammit in the 1800s. It is also interesting to point out that some of the rooms nowadays used as offices used to be the original cells of the Jesuit priests.

The building had quite a turbulent history. A few decades after completion, the structure suffered serious damage in September 1634, caused by an explosion in a nearby gunpowder magazine. This incident led to the re-modelling of certain parts of the building. Eventually the college and church were once again badly damaged in 1693, when an earthquake which hit Sicily in January affected the Island of Malta as well. It is believed that the creation of a sundial on the back of the Jesuits’ church in 1695 and its Latin inscription 'There will be a time where time will cease, and there will be eternal light to the good and endless night to the wicked' was intended as a reminder of the anxious moments experienced during the earthquake. Similarly, there was also the creation of a clock in the courtyard with the Latin inscription 'The Hours Perish and Are Put to Our Account'.

With the expulsion of the Jesuits from Malta in 1768, all their property, including the church and college in Valletta, were seized by the Order and administered by its Treasury. The course of studies, however, continued and the existing professors retained their posts. A conventual chaplain was chosen to take care of the adjacent church in order to keep it open to the public. In 1769, the Order officially established a college and a University on the premises.

After a brief suspension of studies during the reign of Grand Master Ximenes (1773-1775), the University was re-inaugurated in April 1779 by Grand Master de Rohan. From records kept by the Order it has been discovered that public academic debates were already being organised on the premises at the time.

During the French interlude (1798-1800), the University was replaced by the École Centrale, focusing mostly on the natural sciences. Attached to it were the Public Library, a Museum, Botanical Gardens, and an Observatory. Re-organised in 1900 by the British, the latter served as the main source of meteorological observations and records keeping. The equipment was situated in a small room on the highest point on the roof of the building at the corner of Merchants Street & St Christopher Street. In 1906, a seismograph was set up in an underground room making possible the collection of further information.

In the 1800s the British reopened the University, Mgr. Francesco Saverio Caruana being the first Rector. The British also opened a new gateway on St Paul Street in 1824, following the architectural fashion of the time which favoured a Doric revival. The gateway consists of an archway with a free-standing representation in stone of the British royal coat-of-arms on a moulded lintel supported on two Doric fluted columns. An inscription in Greek: 'learning is the gateway to distinction'. Although this entrance is not commonly used anymore, it is still the gateway through which Masters and Doctoral Graduation processions pass before moving on to the Jesuit Church where the actual ceremony is held.

In early British period, the ground floor rooms were rented as the Commercial Rooms, or stanze. In fact this space was re-constructed and refurbished in 1810, and has recently undergone further refurbishment in 2013.

The Old University Building housed a long list of different offices and institutions among them the Anglo-Maltese Library, the Lyceum for male students, an Air Raid Precautions Centre during World War II, and more recently even the head office of Heritage Malta. Nowadays it houses the Conferences and Events Unit (CEU), the Research and Innovation Development Trust (RIDT), and the Centre for the Study and Practice of Conflict Resolution. Part of the building also houses the offices of the International Institute for Justice and the Rule of Law (IIJ).

For more historical and artistic details about the structure, one can consult Michael Ellul’s 'The Jesuit College and Church in Valletta'.