Hostilian was briefly Roman emperor in 251. Hostilian was born to Decius and Herennia Etruscilla at an unknown date and elevated to caesar in 250 by Decius. After Decius and Herennius Etruscus, Hostilian's brother, were killed at the Battle of Abritus, an ambush by the Goths, Trebonianus Gallus was proclaimed emperor by the legions. Almost immediately, he elevated Hostilian to co-emperor and his own son, Volusianus, to caesar. Hostilian died soon after, either due to plague or being murdered by Trebonianus Gallus.

Gaius Messius Quintus Trajanus Decius, known as Trajan Decius or simply Decius, was Roman emperor from 249 to 251.