Flight Leonardo da Vinci–Fiumicino Airport departs from Rome Leonardo da Vinci–Fiumicino Airport at 15:15 and arrives at Riyadh King Khaled International Airport at 22:25.
The flighttime is about 5h 10m. The distance travelled ("as the bird flies"): 4143 Km. So the average speed is roughly 802 Km.
There is an 2 hour time difference between Rome and Riyadh