Lothar the Lost, volume 4

In Volume 1 time travelers arrive in 1920 to prevent World War 2. They form their own military force and recruit the best from the era. Lothar von Richthofen had a promising career as an officer in the new Terran Fleet, but a mistake caused the Fleet Admiral to suspect his intentions, resulting in exile to another timeline a thousand years in the past.

In Volume 2 Lothar continues his adventures in the 10th Century. As he roams over the ancient world he struggles to recreate what was taken from him. He finds some friends in the Venetian Republic and after the initial shock recedes he begins to make a place for himself in the Old World. 

In Volume 3 Lothar continues to gain status in the Ancient World. His knowledge of tactics and strategies from the future are useful, but will he be happy as Caesar of the West?

In Volume 4 Lothar again widens his horizons. He is the most powerful military figure in the 10th Century, but is there anything higher he could reach for?

All of the Lothar series have beautiful covers by Piere d'Arterie.