Donativum (plural, donativa ) was the name given to the gifts of money dispersed to the soldiers of the Legions or to the Praetorian Guard by the Roman emperors. The purpose of the donativum varied: some were expressions of gratitude for favors received, and others out right bribery for favors expected in return. Donativa were normally rendered at the beginning of each new emperor's reign. During the 2nd and 3rd centuries A.D., this form of bribery became a crucial part of any successful ruler in Rome. Such was the case with many of the soldier-emperors from 235 to 248 A.D. The Praetorian Guard, intimate to the emperor's person, was an even greater threat to security. The cohorts stationed in Rome were difficult to appease and quick to commit assassination. The donativum thus provided a terrific way to purchase the Guards' support and loyalty.

The Emperor Augustus bequeathed the Praetorian Guard a substantial sum in his will, but it was not until Tiberius' reign that gifts of money were thought mandatory. The Praetorian Guard received such gifts for turning a blind eye when Sejanus, their prefect, fell from power. Each Praetorian Guard received 10 gold pieces for refraining from defending Sejanus's. In 41 A.D., after the assassination of Caligula, the Guard supported Claudius, and after a brief time the Senate learned that the Guard had installed him on the throne. Claudius gave them 150 gold pieces, or some 3,750 denarii, to which the senators' 100 sesterces were added annually to commemorate Claudius's accession. The inevitable result of the custom of the donativum was the Praetorians' auctioning of the Empire to Didius Julianus in 193 A.D.

See also Congiarium