Complex sentence: During the three-year-long round-the-world adventure Nakhimov was promoted to the rank of lieutenant, and on accomplishing this long voyage he received his first award, Order of Saint Vladimir IV degree.
Split into simpler sentences: During the three-year-long round-the-world adventure Nakhimov was promoted to the rank of lieutenant. On accomplishing this long voyage he received his first award, Order of Saint Vladimir IV degree.