The Battle of Ad Decimum took place on September 13, 533 between the armies of the Vandals, commanded by King Gelimer, and the Byzantine Empire, under the command of General Belisarius. This event and events in the following year are sometimes jointly referred to as the Battle of Carthage, one of several battles to bear that name. The Byzantine victory marked the beginning of the end for the Vandals and began the reconquest of the west under the Emperor Justinian I.

Flavius Belisarius (Greek: Φλάβιος Βελισάριος; c. 500 – 565) was a military commander of the Byzantine Empire under the emperor Justinian I. He was instrumental in the reconquest of much of the Mediterranean territory belonging to the former Western Roman Empire, which had been lost less than a century prior.

One of the defining features of Belisarius' career was his success despite varying levels of available resources. His name is frequently given as one of the so-called "Last of the Romans".

He conquered the Vandal Kingdom of North Africa in the Vandalic War in nine months and conquered much of Italy during the Gothic War. He also defeated the Vandal armies in the battle of Ad Decimum and played an important role at Tricamarum, compelling the Vandal king, Gelimer, to surrender. During the Gothic War, he took Rome and then held out against great odds during the siege of Rome.

He also won an important battle against the Persians at Dara but was defeated at Callinicum. He successfully repulsed a Hunnish incursion at Melantias. He was also known for military deception; he repulsed a Persian invasion by deceiving their commander and lifted the siege of Ariminum without a fight.