Barbary lions

Lion skulls from the Tower of London

Two lion skulls found during excavations at the Tower of London originated in north-west Africa, genetic research suggests.

The big cats, which were kept by royals during medieval times, have the same genetic make-up as the north African Barbary lion, a DNA study shows.

...

The two well-preserved lion skulls were recovered during excavations of the moat at the Tower of London in 1937. They have been radiocarbon dated to AD 1280-1385 and AD 1420-1480.

BBC News.

Lions once lived throughout Africa, into the Middle East and Northwestern India. There were even lions in Europe up until about 100 C.E.

The North African variety, called the Barbary Lion or Nubian lion, became isolated from it's Sub-Saharan cousins and developed into what is generally recognized as a separate sub-species. Mitochondrial DNA has been isolated from samples in museum collections, bolstering the evidence of isolation and speciation.

The Tower of London is actually a complex of fortifications and thirteen towers. Over time it has been the site of a royal residence, an armory, a prison and a menagerie.

Apparently, the Tower moat was used for over one hundred years as a place to dispose of expired lions.