Complex sentence: He made advanced studies in Geology at the same University from 1921 to 1923, and was also assistant in that matter in that university, as well as in those of Pavia (1923-1924) and Milan (1924-1927).
Split into simpler sentences: He made advanced studies in Geology at the same University (1921-1923). He was assistant in Geology at the Universities of Florence (1921-1923), Pavia (1923-1924) and Milan (1924-1927).