Any mention of the Croats before the 9th century is uncertain, and there were several loose attempts at tracing; "Struhates", "Auhates", and Krobyzoi by Herodotus, "Horites" by Orosius in 418 AD, and the "Harus" (original form "Hrws", some read "Hrwts"; "Hros", "Hrus") at the Sea of Azov, near the mythical Amazons, mentioned by Zacharias Rhetor in 550 AD. The "Hros" some relate to the ethnonym of the Rus' people. The distribution of the Croatian ethnonym in the form of toponyms in later centuries is considered to be hardly accidental because it is related with Slavic migrations to Central and South Europe.