During the Ottoman Empire, male heirs were locked in a part of the Imperial palace called kafes (“the cage”). They lived under guard and house arrest unless they succeeded the throne. This was to avoid a war of succession and ensure the survival of the royal dynasty. – WTF Fun Facts
Ottoman empire
WTF Fun Fact – Batman Unit
During the Ottoman Empire a ‘batman’ was a unit of weight equivalent to the modern day 7 lbs and 5 ounces. – WTF Fun Facts
Source: https://en.wikipedia.org/wiki/Batman_(unit)