Entwined African and Asian genetic roots of medieval peoples of the Swahili coast https://www.nature.com/articles/s41586-023-05754-w

"A key finding of this study is evidence of mixture at roughly AD 1000 between peoples of African and Persian ancestries [...]

This is consistent with the Kilwa Chronicle, which describes the arrival of Persians on the Swahili coast and interactions between them and coastal residents. Whether or not this history has a basis in an actual voyage, the ancient DNA provides direct evidence for Persian-associated ancestry being derived overwhelmingly from males and arriving on the eastern African coast by about AD 1000

This timing coincides with archaeological evidence for a substantial cultural transformation on the coast, including the widespread adoption of Islam [...]

Persian loanwords contribute up to 3% of Kiswahili, but it is unclear whether they are derived directly from Persian or through adoption into other Indian Ocean languages"