Gabriel Bethlen made tremendous efforts in order to establish and consolidate the college, hoping that this institution would become an heir to the University of Heidelberg, which had been destroyed in 1622. In his last will, he endowed the college in Alba Iulia with 20,000 florins, plus the annual tax revenue of the town of Debrecen, an expensive necklace and a valuable grape producing domain in the Tokay region. The prince also granted to the college the town of Aiud, with the villages Aiudul de Sus, Mirăslău, Măgina and Hilda, along with portions of Valea Izvoarelor, Decea and Henig. The construction of the college began in the last years of Prince Bethlen’s reign, from 1627 to 1629, and continued in the reign of George Rákóczi I, between 1630 and 1648. The buildings of the college were erected on plots of land purchased by the princes during the periods 1627-1629 and 1632-1637.

The lay school functioned in number 12 Romana Street, a building which is located at the crossroads with Unirii Street. The building displays architectural features typical of the late Transylvanian Renaissance. The massive building consists of two wings, having inner courtyards in the shape of irregular quadrangles separated by a single-storey building. Pairs of gates emplaced on the southern and northern sides allowed access into the inner courtyards.The gates had passageways covered by semi-cylindrical vaults with penetrations. The design of the edifice is exactly as shown in a 1711 drawing by Giovanni Morando Visconti, and in another illustration of 1736.

In 1629, the Collegium Academicum Bethlenianum was elevated to the rank of academic school (Academicum Collegium seu Gymnasium illustre) with three faculties: theology, philosophy and philology. The courses taught included Hebrew, Greek, Latin, theology, philosophy, rhetoric, poetics, and Romanian language. The students were recruited from among the nobility and urban dwellers. The school had 40 students whose tuition and living expenses were covered directly from the budget of the princely household. The institution trained the young men for various lay careers and offices of the principality.

The prestige of this school was ensured by professors from both Transylvania and elsewhere in Europe. Among the Transylvanian professors were Paul Keresztúri, Stephen Geleyi and George Stephen Csulai. The last named of these paid for the printing of the first Romanian books in Alba Iulia. Also noteworthy is János Apáczai Csere (1625-1659), student and then professor of the college of Alba Iulia, who later completed his academic studies in Utrecht, the Netherlands.

In the academic year 1622-1623, the Silesian Martin Opitz (1597-1643), who is regarded as the father of German literature, taught the Classical authors in the college. Other prestigious professors were James Copius, the famous historian and philosopher Johann Heinrich Alsted (1588-1638), and Johann Heinrich Bisterfeld (1606-1655), the renowned naturalist of that age. The last named enjoyed favour in the princely court and was entrusted with various diplomatic missions in the country and abroad. Isaac Basirius (1607-1676), born in France, went for studies in the Netherlands and was later appointed to high offices in England.Then he became a missionary in the Orient, where he met Acatius Barcsai, the envoy of the Principality of Transylvania to Istanbul. Basirius served as a Calvinist priest in Galata, Istanbul, and was invited as a professor to Alba Iulia, to replace Bisterfeld.He was rector for about three years, until 1658, when he was forced to leave the city by the unexpected events stirred by the Tatar invasion.

Princes reigning after Gabriel Bethlen and George Rákóczi I did not understand and support the institution; regarding the college as a personal achievement of their forerunners, they felt unable to maintain this important investment in Alba Iulia. Further, the college was set on fire in 1658, during the invasion led by the Ottoman Grand Vizier Mehmed Köprülü against George Rákóczi II, when the fortress was also severely damaged. The institution disappeared in this disaster, striking the city on 5-6 September. In addition to the sacking of the college, the invaders killed the 53 students who were hiding in the towers of the churches. Prince Michael Apafy I ordered that the professors and students of Alba Iulia be moved to Aiud, and then established the college of that city in 1662. The college was repaired only around 1672, when the professors and students of the Calvinist school in Sárospatak temporarily took refuge in Alba Iulia. In 1716, during the modernisation of the Alba Iulia fortress, the building was occupied by the army and turned into a barracks, the school being transferred to Târgu Mureș.(L.S.)