Charlemagne and cheetahs

[Flavivs Aetivs]

I've seen in several places that Charlemagne kept a few cheetahs, I was wondering if anyone on here actually had a source on that?

Cheetahs are depicted in Greek and Roman art (Latin: Felices Ivbatvs), and were owned as pets in Ancient Egypt, Persia, and India.

Thanks,
MMFA