Complex sentence: In March 1922, Prokofiev moved with his mother to the town of Ettal in the Bavarian Alps, where for over a year he concentrated on an opera project, "The Fiery Angel", based on the novel "The Fiery Angel" by Valery Bryusov.
Split into simpler sentences: In March 1922, Prokofiev moved with his mother to the town of Ettal in the Bavarian Alps for over a year so he could concentrate on composing. Most of his time was spent on an opera project, "The Fiery Angel", based on the novel "The Fiery Angel" by Valery Bryusov.