Complex sentence: After the first war, Bologna began to become more successful; first reaching the semi-finals of the Northern Italian competition in 1919--20, they went one better the following season by reaching the Northern League finals; going out 2--1 to Pro Vercelli.
Split into simpler sentences: After the first war, Bologna began to become more successful. First reaching the semi-finals of the Northern Italian competition in 1919--20, they went one better the following season by reaching the Northern League finals, going out 2--1 to Pro Vercelli.