Complex sentence: He gained power by subverting the Lasakau people to plot and execute an overthrow of the Roko Tui Bau Vuani-ivi clan lead by Ratu Ravulo Vakayaliyalo In 1837 and reinstated his father as the ruling Vunivalu ni Bau.
Split into simpler sentences: He gained power by persuading the Lasakau people to plot and execute an overthrow of the Roko Tui Bau Vuani-ivi clan lead by Ratu Ravulo Vakayaliyalo in 1837. Seru then reinstated his father as the ruling Vunivalu ni Bau.