Kafes

Kafes, literally "the cage", was the part of the Harem of the Ottoman Palace where possible successors to the throne were kept under constant surveilence by the palace guards.

Early history of the Ottoman Empire is littered with succession wars between rivaling sons of the deceased sultan. Therefore it was almost the law that once the new sultan ascended to the throne, he had his brothers killed, sometimes dozens of them at once, including infants. Although this practice effecively reduced the number of claimants to the throne, there were several occasions where the Ottoman line seemed destined to end. Hence, during the latter stages of the Ottoman Empire, in order to prevent Ottoman line's end the succession rule has changed to the "rule of elderness", meaning upon the death of the current ruler, the next ruler would be the eldest male member of the Ottoman dynasty whose father was a sultan. Although this effectively nilled the risk of the Ottoman line ending, it resulted in many male members of the Ottoman dynasty spending their whole lives under captivity in the Kafes as sultans were always -with reason- worried about palace coups to replace them with another member of the dynasty. This of course had a great impact on the personalities on the captives in the Kafes and many of them grew psychological disorders.