In spite of the acknowledged dominance of the Kushana empire during his reign, scholars have not been able to agree on the period of his reign. This issue has not been resolved even after three conferences convened to tackle it. According to the Chinese scholar Huan Tsang, Kanishka ascended to the throne 400 years after the death of Buddha. This date places his ascension to about 50 BC. However this date has been ruled out as inconsistent withe everything else known about the region. Detailing the controversy regarding his period of reign is beyond the scope of this article. The interested reader is encouraged to follow the external links below. Most recent debate however has focused around the relatively narrow period between 78 and 128 AD as the likely date of ascension.
Kanishka's empire was certainly vast. It extended from the Oxus in the west to Varanasi in the east and from Kashmir in the North to the cost of Gujarat in the south, including Malwa. Knowledge of his hold over Central Asia is less well established. Chinese records indicate that general Pan-Chao defeated a Kushan army at Khotan in 90 AD. Also controlling the land and sea trade routes between India and Rome seems to have been one of Kanishka's chief imperial goals.
A great deal of information about the Kushana kings has been gathered from their coins. Kanishka's coins show Hindu, Buddhist, Greek, Persian and even Sumerian-Elamite images of gods. This is demonstrative of religious syncretism in his beliefs. His reputation in Buddhist tradition is based mainly on his having convened a great Buddhist council in Kashmir. This council is attributed with having encouraged the spread of Mahayana Buddhism. His greatest contribution to Buddhist architecture is the great stupa at Peshawar. Archaeologists in the twentieth century ascertained that this stupa had a diameter of 286 feet. Reports of Chinese pilgrims indicate that its height was 600 to 700 feet. Certainly this would rank among the wonders of the ancient world. He provided encouragement to both the Gandhara school of Buddhist art and the Mathura school of Hindu art (An inescapable religious syncretism pervades Kushana rule). Kanishka personally seems to have embraced both Buddhism and the Persian Mithras cult.
Kanishka was probably succeeded by Huvishka. How and when this came about is still uncertain. The fact that there were other Kushana kings called Kanishka is just another complicating factor.