Last Act in Palmyra is the sixth in the Falco series by Lindsey Davis - and the first after she ran out of metals (silver, bronze, copper, iron and gold) to put in the titles. It's still a good book

, and it has dropped to £0.99 at Kindle UK right now.
Kindle UK:
https://www.amazon.co.uk/dp/B004NBZFWK
Kindle UK/Smile:
https://smile.amazon.co.uk/dp/B004NBZFWK