Sarosios was the King of the Alans in the early 6th century while they were still in Ukraine. He acted as diplomatic negotiator between the Central Asian Pseudo-Avar refugees led by Kandik and Justinian I in 557 and then again between Justin II and the Turks in 569 from whom we learn the Avars who Sarosios helped in 557 were in fact renegades from the Hephthalites (who surrendered to the Göktürks & Persia in 567) and apparently had no right to use the title Avar Khagan. The diplomatic ties that Sarosios fostered led to the Göktürk's agreement with Emperor Maurice, in 598, to support a ruler, Sandilch, approved of by the Ashina clan.
- Theophylact Simocatta, Ed. Bonn, 282ff, Chavannes, Documents, 246ff