Trajan is the current emperor of Rome. He was came to power in 98 A.D. following the death of Nerva, who had been forced to name him his successor just a year earlier. Trajan was a general before becoming the emperor, and his military forays did not cease upon taking the throne. In 107 he conquered Dacia, a region to the west of the black sea, and has just started celebrating this victory with the Dacian Games.
Trajan is a wildly popular emperor amongst romans, and even towards Christians he is lenient. He has instructed Pliny to leave them alone unless they were openly practising their religion.