Bardas belonged to the great family of the Skleroi, which owned enormous estates at the eastern outskirts of Asia Minor. His mother Gregoria descended from Basil I's brother Bardas. The greatest coup of his early career was a brilliant defense of Constantinople against the army of Svyatoslav I of Kiev in 970. During the Battle of Arcadiopolis, he reportedly managed to inflict as many as 20,000 casualties on the Rus, while the campaign claimed the lives of merely 25 Greek soldiers.