Complex sentence: The second group was private commissions that he obtained, consisting of portraits and cemetery monuments and the third collection consisted of the private works that he labored over as he became increasingly and deeply spiritually attuned and reclusive.
Split into simpler sentences: The second group was private commissions that he obtained, consisting of portraits and cemetery monuments. The third collection consisted of the private works that he labored over as he became increasingly and deeply spiritually attuned and reclusive.