The new monograph of doctor of historical sciences, professor Igor Oleg Князького is sanctified to life and activity of one of the glorified Roman emperors is Марка Ульпия Trajan. First provincial at the head of Empire as nobody other from the rulers of Rome deserved nickname of "Optimus Princeps" (The best Принцепс). Trajan succeeded in the years of his rule, it would seem, impossible, if to remember experience of his predecessors : to connect concepts "Принципат" and "Freedom". He became the last Roman emperor deciding on large aggressive hikes.On the basis of wide circle of sources and researches an author analyses the course of life of Mark Ульпия Trajan, feature of his domestic policy, wars with Dacia and hike on Парфию. Especially paid attention to position of christians in the Roman empire in the years of rule of Trajan.A monograph is intended for a wide circle readers.