Soviet troops continued their push on Serbia, capturing Nish in early February. The Soviet 5th Army from Greece met with the Romanian First and the Bulgarian Second at Nish in late February. The huge armies were ready to push on Belgrade. By March, the Soivet armies were around Belgrade, ready for the order to march into the Serbian capital. Petr I of Serbia fled to Vienna. Finally, in June 1919, Belgrade fell. The Soviet armies continued across the border into Austria-Hungary, destroying towns on their way to Vienna. The Austro-Hungarian High Command decided to retreat towards the Adriatic Coast. The Soviet forces continued into Budapest, which was captured in August. Meanwhile, the Austro-Hungarian Army had completed their retreat into the mountains. With it, the Austrians took all the f