Flight Dulles International Airport departs from Washington Dulles International Airport at 16:30 and arrives at Rome Leonardo da Vinci–Fiumicino Airport at 07:15.
The flighttime is about 9h 45m. The distance travelled ("as the bird flies"): 9976 Km. So the average speed is roughly 1023 Km.
There is an 5 hour time difference between Washington and Rome
