The Danube campaign opens when the Russians occupy the Danubian Principalities of Moldavia and Wallachia in May 1853, bringing their forces to the north bank of the River Danube.

In response, the Ottoman Empire also moves its forces up to the river, establishing strongholds at Vidin in the west and Silistra in the east, near the mouth of the Danube.

The Ottoman move up the River Danube is also of concern to the Austrians, who move forces into Transylvania in response.

However, the Austrians have begun to fear the Russians more than the Turks.

Indeed, like the British, the Austrians are now coming to see that an intact Ottoman Empire is necessary as a bulwark against the Russians.

Accordingly, Austria resists Russian diplomatic attempts to join the war on the Russian side and will remain neutral in the Crimean War.