Marcus Didius Severus Julianus (133/137 - June 1, 193) reigned as Roman Emperor from March 28 to June 1 of AD 193. He became emperor by winning an auction the Praetorian Guard held for the title. He was killed upon Septimius Severus's arrival in Italy.
Julianus was born to Quintus Petronius Didius Julianus and Aemilia Clara, a noble family from Milan.
Julianus won the auction to become emperor with a bid of 25,000 sesterces to each member of the Praetorian Guard, outbidding City Prefect Titus Flavius Sulpicianus.
His date of birth is given as January 30, 133 by Cassius Dio and February 2, 137 by Historia Augusta.