A pair of lion skulls excavated from the moat around the Tower of London and dating to the medieval period belong to an extinct subspecies of Barbary lion which died out in the early 1920s, a study has found.

An analysis of the DNA extracted from the skulls has found that both lions share the same genetic traits as the large subspecies which had distinctive black manes and once lived in the Morocco region of north-west Africa until it disappeared nearly a century ago.

The two skulls were first recovered from the Tower’s moat during excavations in 1936 and 1937 but the precise geographical origin of the famous lions of the Royal Menagerie – first established by King John who reigned between 1199 and 1216 – was unknown.

Download the new Independent Premium app Sharing the full story, not just the headlines

“Until now we didn’t have any strong evidence that they were from North Africa. There was no documentary evidence for instance. They could have come from Asia or even from other parts of the Mediterranean,” said Richard Sabin, curator of mammals at the Natural History Museum in London.

“Lions are very charismatic large cats that have been imported into Europe for various purposes since early historic times. We’ve not known, however, until now the exact geographical origin of the animals found in London,” Dr Sabin said.

“Our results are the first genetic evidence to clearly confirm that lions found during excavations at the Tower of London originated in north Africa,” he added.

Radiocarbon tests on the skulls show that one is dated to between 1280 and 1385 and the other is dated to between 1420 and 1480. Both were young males of about three or four years of age and could have been born in the Royal Menagerie at the Tower of London rather than been shipped directly from north Africa, Dr Sabin said.

“Barbary lions were probably the largest of all the subspecies of lion. They had very long, black, shaggy manes and would have been very imposing. Visitors to the King would have had to pass through Lion Tower where the cats were kept in cages,” he said.

Nobuyuki Yamaguchi, who carried out the genetic analysis of the lions’ bones said that a contiguous population of lions once stretched from north Africa through the Middle East to India, until the growth of the Egyptian civilisation about 4,000 years ago divided the lions into separating breeding populations. “Western north Africa was the nearest region to Europe to sustain lion populations until the early 20th Century, making it an obvious and practical source for medieval merchants,” Dr Yamaguchi said.

“Apart from a tiny population in northwest India, lions had been practically exterminated outside sub-Saharan Africa by the turn of the 20th Century.”

The Royal Menagerie was first established in Woodstock near Oxford before being relocated to the Tower of London. The first residents were three leopards sent to Henry III by the Holy Roman Emperor Frederick II in 1235. It later on housed a number of exotic animals and was effectively the private zoo of successive kings and queens until it was closed by the Duke of Wellington in 1835 and the contents transferred to Regent’s Park to become London Zoo.

“Although we have one of the best mammal collections in the world here at the Natural History Museum, few physical remains survive of the Royal Menagerie,” Dr Sabin said.

“Direct animal trade between Europe and sub-Saharan Africa was not developed until the 18th Century, so our results provide new insights into the patterns of historic animal trading,” he said.