is known from Chinese sources that An Shigao (fl. 2nd century AD), a Parthian nobleman and Buddhist monk, traveled to Luoyang in Han China as a Buddhist missionary and translated several Buddhist canons into Chinese. Art and architecture Parthian art can be divided into three geo-historical phases: the art of Parthia proper; the art of the Iranian plateau; and the art of Parthian Mesopotamia. The first genuine Parthian art, found at Mithridatkert/Nisa, combined elements of Greek and Iranian art in line with Achaemenid and Seleucid traditions. In the second phase, Parthian art found inspiration in Achaemenid art, as exemplified by the investiture relief of Mithridates II at Mount Behistun. The third phase occurred gradually after the Parthian conquest of Mesopotamia. Common motifs of the Parthian period include scenes of royal hunting expeditions and the investiture of Arsacid kings. Use of these motifs extended to include portrayals of local rulers. Common art mediums were rock-reliefs, frescos, and even graffiti. Geometric and stylized plant patterns were also used on stucco and plaster walls. The common motif of the Sasanian period showing two horsemen engaged in combat with lances first appeared in the Parthian reliefs at Mount Behistun. In portraiture the Parthians favored and emphasized frontality, meaning the person depicted by painting, sculpture, or raised-relief on coins faced the viewer directly instead of showing his or her profile. Although frontality in portraiture was already an old artistic technique by the Parthian period, Daniel Schlumberger explains the innovation of Parthian frontality: 'Parthian frontality', as we are now accustomed to call it, deeply differs both from ancient Near Eastern and from Greek frontality, though it is, no doubt, an offspring of the latter. For both in Oriental art and in Greek art, frontality was an exceptional treatment: in Oriental art it was a treatment strictly reserved for a small number of traditional characters of cult and myth; in Greek art it was an option resorted to only for definite reasons, when demanded by the subject, and, on the whole, seldom made use of. With Parthian art, on the contrary, frontality becomes the normal treatment of the figure. For the Parthians frontality is really nothing but the habit of showing, in relief and in painting, all figures full-face, even at the expense (as it seems to us moderns) of clearness and intelligibility. So systematic is this use that it amounts to a complete banishment de facto