Dr Piotr Letki (born 1981) – historian, MA graduate in Opole University’s Institute of History, where in 2005, on Faculty of History and Pedagogy he has written thesis on subject “Legiony rzymskie okresu Cesarstwa w świetle >>Zarysy wojskowości<< Flawiusza Wegecjusza Renatusa”. In 2010 he made his PhD in Opole University. Thesis entitled “Uzbrojenie I taktyka walki jazdy rzymskiej w czasach panowania cesarza Dioklecjana 284-305 n.e.” under supervision and tuition of Professor Joanna Rostropowicz. He is interested in history of Ancient Rome, especially military matters, particularly Roman Cavalry in 3rd and 4th centuries AD. (organisation, armament and tactics). He published articles in Studia nad kulturą antyczną, Studia Historyczno-Wojskowe, Przegląd Historyczno-Wojskowy i Gazeta Rycerska.