Complex sentence: In 1712, together with Yakov Permyakov, Merkury Vagin explored the region of the eastern Laptev Sea coast, including Bolshoy Lyakhovsky Island, the southernmost of the New Siberian Archipelago.
Split into simpler sentences: In 1712, together with Yakov Permyakov, Merkury Vagin explored the region of the eastern Laptev Sea coast. His exploration included Bolshoy Lyakhovsky Island, the southernmost of the New Siberian Archipelago.