Complex sentence: At the beginning of the 17th century the empire contained 32 provinces and numerous vassal states, some of which were later absorbed into the empire, while others were granted various types of autonomy during the course of centuries.
Split into simpler sentences: At the beginning of the 17th century the empire contained 32 provinces and numerous vassal states. Some of these were later absorbed into the empire, while others were granted various types of autonomy during the course of centuries.