Complex sentence: In a non-literate society they were the repositories of knowledge, including not just stories and songs, but also genealogies and medicine and were found in many of the courts of the great lords, down to the chiefdoms of the highlands at the beginning of the period.
Split into simpler sentences: In a non-literate society they were the repositories of knowledge, including not just stories and songs, but also genealogies and medicine. They were found in many of the courts of the great lords, down to the chiefdoms of the highlands at the beginning of the period.