From the lowest slaves to the highest-ranking ministers, for almost four thousand years eunuchs were a presence in courts across the world. As a social class of trusted servants, eunuchs served Egyptian pharaohs, Chinese emperors, middle-eastern kings, caliphates and sultans, and in many places became well-respected confidants, advisors, generals and patriarchs. But their unique position often led to their ability to amass great power. At their height in Imperial China during the Middle Ages, the eunuchs were the kingmakers. They became feared masters of court intrigue, open to corruption, interfering with politics, selecting successors, and able to destroy their enemies to keep themselves strong.