He returned to Florence , and `` being of a sophistical turn of mind , he there wrote a commentary on a portion of Dante and illustrated the Inferno which he printed , spending much time over it , and this abstension from work led to serious disorders in his living . '' He returned to Florence , and `` being of a sophistical turn of mind , he there wrote a commentary on a portion of Dante and illustrated the Inferno which he printed , spending much time over it , and this abstention from work led to serious disorders in his living . ''