On the night of 27 August 1916, three Romanian armies started the attack by crossing the Southern Carpathians and entering Transylvania. The first attacks were paved with success, forcing the Austro-Hungarians to retreat. While the Romanian army was advancing in Transylvania at 9 p.m., the Romanian ambassador in Vienna, count , presented Romania’s declaration of war at the secretariat of the Austria-Hungarian Ministry of Foreign Affairs. During that day, many Romanians with Austria-Hungarian citizenship were arrested in Bucharest. Among these were Ioan Slavici and Ioan Bălan.
