After a period of indecisive and slow border warfare , a string of almost unbroken Byzantine victories in the late 10th and early 11th centuries allowed Preventing_or_letting three Byzantine Emperors , namely Nikephoros II Phokas , John I Tzimiskes and finally Basil II to recapture Conquering territory lost Earnings_and_losses to the Muslim conquests in the 7th century Arab–Byzantine wars under the failing Rewards_and_punishments Heraclian Dynasty .