Arista refers to the pork saddle. In Tuscany it is usually cooked on the spit but it can also be delicious roasted in the oven.
The story, as told by the author Pellegrino Artusi in the historic Italian cookbook “L’Arte di Mangiar Bene” goes back to the year 1430 in Florence. At that time, the leaders of the Roman Catholic and Greek Orthodox churches were having a church council meeting. When the Tuscans served this roast to the Greek bishops, they all exclaimed “Aristos, aristos, aristos!” (the best) in Greek. From that day forward, the Tuscans have called this roast Arista.