Complex sentence: This undertaking, lasting from 1728 to 1730, was led by the Danish captain Vitus Jonassen Bering (1681--1741), an officer in the Russian imperial navy since 1704.
Split into simpler sentences: This undertaking, lasting from 1728 to 1730, was led by the Danish captain Vitus Jonassen Bering (1681--1741). Bering had been an officer in the Russian imperial navy since 1704.