Complex sentence: In 1918, the short-lived "Odessa Soviet Republic" declared its independence (OSR;;;) was a short-lived Soviet republic formed on from parts of the Kherson and Bessarabia Governorates of the former Russian Empire.
Split into simpler sentences: In 1918, the "Odessa Soviet Republic" declared its independence (OSR;;;). It was a short-lived Soviet republic formed on from parts of the Kherson and Bessarabia Governorates of the former Russian Empire.