On the middle course of Mureș, at the entry of Apuseni Mountains fortress and at the north end of the transylvanian plateau, there is evidence of the existence of some tribes of farmers and shepherds dating from the Neolitic era. Proofs that this land was inhabited were also found further on the chronological axis, in the Bronze and Iron ages.
Later on, the ancient dacians inhabited this area, building an important fortress of Dacia - Apoulon Citadel. As a consequence of the Roman conquest from 106 AD Christ a permanent Roman camp was build with the purpose of guarding the entrance in this territory which was rich in gold and to secure the transportation of gold towards Rome. The basis of the Roman administration from Dacia were set in Apulum due to two cities built around the Roman camp: Colonia Aurelia Apulensis and Colonia Nova Apulensis.
The development of these urban centers was put to an end somewhere in the obscurity of a history marked by migrations, wars and massacres. The sources attest the existence of a medieval fortress in 1199, named Alba Iulia, after the White(Alba) Citadel of Gyula (Iulia).
Subsequently the Citadel is referred to as the capital city of the Voivodship and further on of the Principality of Transylvania and also residence of the Catholic Diocese of Transylvania.
Alba Iulia Citadel is the cradle of the idea of unity for Romanians since the triumphant entrance in the city of voivod Michael the Brave, who declared the city the capital of all Romanians on 1 November 1599.
The Austrian rule instituted after 1700 converted the medieval city into a military bastion inspired by the model of the French engineer Vauban Sébastien Le Prestre. Constructions were carried out between 1714-1738, with a defensive system conceived of three rows of walls fortified by seven towers and enclosed by three lines of ditches.
The Citadel witnessed the tragic end of the three leaders of the revolt of 1785 - Horea, Cloșca and Crișan.
In the line of great historical events which took place in Alba Iulia there is also the Grand National Assembly of December 1st 1918, which is the expression of the Romanians’ desire to unify.
King Ferdinand and Queen Marie glorified the importance of Alba Iulia for the history of the Romanian people through an official ceremony of coronnation as king and queen of all the Romanians from the united historical provinces, held on October 15th 1922.
Every year, on December 1st, in Alba Iulia the first unification of the Romanian people is celebrated through events which confirm its role of a Hallmark-Citadel of the Great Union of Romanians.