Complex sentence: From 1921 to 1925, he lived with his family in Vigo which they left to go and live in Madrid where Cela was able to study at a Piarist school.
Split into simpler sentences: From 1921 to 1925, he lived with his family in Vigo where they ended up leaving in order to go and live in Madrid. It was here Cela was able to study at a Piarist school.