Following the diplomatic venture of Zhang Qian into Central Asia during the reign of Emperor Wu of Han (r. 141–87 BC), the Han Empire of China sent a delegation to Mithridates II's court in 121 BC. The Han embassy opened official trade relations with Parthia via the Silk Road yet did not achieve a desired military alliance against the confederation of the Xiongnu. The Parthian Empire was enriched by taxing the Eurasian caravan trade in silk, the most highly priced luxury good imported by the Romans. Pearls were also a highly valued import from China, while the Chinese purchased Parthian spices, perfumes, and fruits. Exotic animals were also given as gifts from the Arsacid to Han courts; in 87 AD Pacorus II of Parthia sent lions and Persian gazelles to Emperor Zhang of Han (r. 75–88 AD). Besides silk, Parthian goods purchased by Roman merchants included iron from India, spices, and fine leather. Caravans traveling through the Parthian Empire brought West Asian and sometimes Roman luxury glasswares to China. The merchants of Sogdia, speaking an Eastern Iranian language, served as the primary middlemen of this vital silk trade between Parthia and Han China.