For 10 points, name this empire that was on the western end of the Silk Road and was based in Italy.
Gān Yīng's account of this state describes a mistaken belief that this state produced a textile from the down of "water sheep." That account describes how Ānxī thwarted this state's attempts to send out envoys, and calls this state DÃ qÃ­n ("dah-chin"). On the behalf of this empire, two monks hid mulberry seeds and silkworm eggs in their walking sticks to steal the secret of making silk. A monument that commemorates the propagation of a "luminous (*) religion" originating in this empire was erected during the TÃ¡ng dynasty. That monument, the Nestorian Stele, is inscribed with several names in Syriac. The ancient Chinese mistakenly thought that this empire's capital was Ān-tū, or Antioch. For 10 points, name this empire that was on the western end of the Silk Road and was based in Italy.
Gān Yīng's account of this state describes a mistaken belief that this state produced a textile from the down of "water sheep.
Roman Empire [or Rome; accept Byzantine Empire or Byzantium; accept DÃ qÃ­n until read]