History of Transylvania union of Transylvania with Romania in Alba Iulia on 1. December 1918.; Bessarabia, having declared independence from Russia in 1917 at the Conference of the Country (Sfatul Țării), called in Romanian troops to protect the province from the Bolsheviks. The union of the Transylvania, Maramureș, Crișana and Banat regions with the Old Kingdom of Romania was ratified in 1920 by the Treaty of Trianon, which recognised the sovereignty of Romania over these regions and settled the border between the Republic of Hungary and the Kingdom of Romania. The union of Bukovina and Bessarabia with Romania was ratified in 1920 by
Celts in Transylvania area. The Celts exercised politico-military rule over Transylvania between the 4th and 2nd century BC and brought with them a more advanced iron-working technology. They were also responsible for the spread of the potter's wheel into a much wider area than the one they occupied. Large areas of ancient Dacia, which were populated early in the First Iron Age by Thracian people, were affected by a massive migration of Iranian Scythians moving east to west during the first half of the first millennium BC. They were followed by a second equally large wave of Celts migrating west to east. Celts