Complex sentence: During the brief period of Ukrainianization the ensemble grew in popularity, however, in the 1930s the political situation in Ukraine changed significantly and bandurists underwent various forms of political repression: some being arrested and sentenced to periods of incarceration, others to exile.
Split into simpler sentences: During the brief period of Ukrainianization the ensemble grew to become became extremely popular, however, in the 1930s the political situation in Ukraine changed. Many bandurists underwent various forms of political repression: some being arrested and sentenced to periods of incarceration, others to exile.