The Kizlar Agha (, , "Agha of the [slave] Girls"), formally the Agha of the House of Felicity (Arabic: Aghat Dar al-Sa'ada, Turkish: Darüssaade aga), was the head of the eunuchs who guarded the Imperial Harem of the Ottoman Sultans in Constantinople. Due to his proximity to the Sultan and the role the harem ladies played in court intrigues, the post ranked among the most important in the Ottoman Empire until the early 19th century. Soon after its creation and until its abolition at the end of the Ottoman Empire, the post came to be occupied by Black African eunuch slaves, and hence is also referred to as the Chief Black Eunuch.