Dacica (or De bello dacico) is a Latin work by Roman Emperor Trajan, written in the spirit of Julius Caesar's commentaries like De Bello Gallico, and describing Trajan's campaigns in Dacia.It is assumed to be based on Criton of Heraclea's Getica, a work on the history of the Daco-Getae. Criton was Trajan's Greek chief physician and procurator, during the Dacian wars.Based on the research so far, Dacica is considered lost. However, one sentence survived in the Latin grammar work by Priscian.