While a centurion, Sulpicius Similis' actions during Trajan's First Dacian War brought him to the emperor's attention. According to an anecdote in Dio Cassius, the emperor also appreciated his humble, honest character. This favour allowed Similis to skip the steps of the equestrian "tres militiae", which were normally required to hold the senior imperial equestrian posts. An excerpt of Ulpian states that around 106 Similis was named "Praefectus annonae", or overseer of the grain supply for the capital city of Rome.