Leopold I (also Luitpold), known as the Illustrious (German: der Erlauchte), a member of the House of Babenberg, was Margrave of Austria from 976 until his death. He was the first margrave of the Babenberg dynasty which ruled the March and Duchy of Austria until its extinction in 1246.
The origins of Leopold the Illustrious are not known. According to early traditions, documented by Bishop Otto of Freising in the twelfth century, he is descended from Duke Henry of Franconia and the Elder Babenberg family (Popponids) whose genealogy is documented in Franconia Nobility.
After Emperor Otto I had defeated the Magyars in the 955 Battle of Lechfeld, he re-established the Bavarian Marcha orientalis (Eastern March) in the conquered territories, placing them under the command of Margrave Burkhard, a brother-in-law of Duchess Judith, consort of Duke Henry II of Bavaria. When Burkhard joined the uprising of Duke Henry II ("the Wrangler") against Emperor Otto II, he was deposed at the Imperial Diet of Ratisbon in 976. According to a charter dated 21 July 976, loyal Leopold was appointed margrave of the Marcha orientalis, the core territory of the later Archduchy of Austria.
Leopold ruled over the re-established Marcha orientalis for eighteen years. He organized and expanded it with great ability, and left behind a margravate that had assumed the character of "an ordered and civilized land".