Roman emperor Aurelian ruled from 270 to 275. His military triumphs reunited the Roman Empire and put an end to the Crisis of the Third Century. He built the Aurelian Walls in Rome. Known as the Restitutor Orbis, he defeated the barbarian armies of the Goths and the Alamanni.
Boris III became Tsar of the Kingdom of Bulgaria in the wake of Bulgaria's defeat in First World War. He is noted for legitimating the 1923 Bulgarian coup d'état and joining Axis Powers during Second World War. He however refrained from participating in German invasion of Soviet Union and resisted attempts of the Germans in deporting Bulgarian Jews during Holocaust.
Krum was the ruler of Bulgaria from 803 until his demise in 814. An able administrator, Krum helped expand the Bulgarian territory, which doubled in size during his reign. Krum is also remembered for introducing the first known written law code in the history of Bulgaria, which established him as a strict but just ruler.
Omurtag of Bulgaria reigned as the Great Khan of Bulgaria between 814 and 831. Nicknamed the Builder, Omurtag's reign was marked with a significant development of Bulgarian architecture as a number of ambitious construction projects were undertaken during his reign. Omurtag of Bulgaria also made strong administrative reforms which enhanced the authority and the power of the central government.