Complex sentence: During this period, in 1565, it also ceased to be a Benedictine abbey and became Lutheran like the city of Magdeburg, and the formal opening of the school was therefore in 1565, as a Lutheran foundation.
Split into simpler sentences: During this period, in 1565, it also ceased to be a Benedictine abbey and became Lutheran like the city of Magdeburg. The formal opening of the school was therefore in 1565, as a Lutheran foundation.