Complex sentence: Its subject matter, the representation of human actions based on themes from history, mythology, literature, and scripture, required extensive learning in biblical and Classical literature, knowledge of art theory and a practical training that included the study of anatomy from the male nude.
Split into simpler sentences: Its subject matter was the representation of human actions based on themes from history, mythology, literature, and scripture. This required extensive learning in biblical and Classical literature, knowledge of art theory and a practical training that included the study of anatomy from the male nude.