Siege of Rome: The Ostrogoth army under king Vitiges begins the siege of the capital. Belisarius conducts a delaying action outside the Flaminian Gate; he and a detachment of his bucellarii are almost cut off.

The first siege of Rome during the Gothic War lasted for a year and nine days, from 2 March 537 to 12 March 538. The city was besieged by the Ostrogothic army under their king Vitiges; the defending East Romans were commanded by Belisarius, one of the most famous and successful Roman generals. The siege was the first major encounter between the forces of the two opponents, and played a decisive role in the subsequent development of the war.

The Ostrogoths were a Roman-era Germanic people. In the 5th century, they followed the Visigoths in creating one of the two great Gothic kingdoms within the Western Roman Empire, drawing upon the large Gothic populations who had settled in the Balkans in the 4th century. While the Visigoths had formed under the leadership of Alaric I, the new Ostrogothic political entity which came to rule Italy was formed in the Balkans under Theodoric the Great.

Vitiges was king of Ostrogothic Italy from 536 to 540. He succeeded to the throne of Italy in the early stages of the Gothic War of 535–554, as Belisarius had quickly captured Sicily the previous year and was in southern Italy at the head of the forces of Justinian I, the Eastern Roman Emperor.

A siege is a military blockade of a city, or fortress, with the intent of conquering by attrition, or by well-prepared assault. Siege warfare is a form of constant, low-intensity conflict characterized by one party holding a strong, static, defensive position. Consequently, an opportunity for negotiation between combatants is common, as proximity and fluctuating advantage can encourage diplomacy.