There isn't one really, but why let that stop us? Ryan is an Irish name derived from the old Gaelic word for king: Righ. The Latin for king is rex which isn't really a name in Latin but there's nothing to stop you using it as a name in English.
Note that Gaelic and Latin are related. They are both members of the Indo-European family of Languages, as is English of course. The Latin word rex and the old Gaelic righ are from the same root.
Note that Gaelic and Latin are related. They are both members of the Indo-European family of Languages, as is English of course. The Latin word rex and the old Gaelic righ are from the same root.
