The Sassanid Empire, lasting the length of the Late Antiquity period, is considered to be one of Iran's most important and influential historical periods. In many ways the Sassanid period witnessed the highest achievements of Persian civilization and constituted the last great Iranian Empire before the Muslim conquest and the adoption of Islam. During Sassanid times, Persia influenced Roman civilization considerably, and the Romans reserved for the Sassanid Persians alone the status of equals. Sassanid cultural influence extended far beyond the empire's territorial borders, reaching as far as Western Europe, China, and India, playing a role, for example, in the formation of both European and Asiatic medieval art.