Of some relevance is his new book that just came out, The Storm Before the Storm[2], which details the events that preceded the rise of Julius Caesar and paved the way for him to overthrow the republic.
[0] https://en.wikipedia.org/wiki/The_History_of_Rome_(podcast)
[1] https://www.reddit.com/r/ancientrome/comments/32lono/every_e...
[2] https://www.amazon.com/Storm-Before-Beginning-Roman-Republic...
A good look into this further is Mike Duncan's The Storm before the Storm that leads into the Sulla era: https://www.amazon.com/Storm-Before-Beginning-Roman-Republic...
Duncan's The History of Rome podcast is very good overall and very much worth a listen.