In 250 BC, the Central Asian portion of the empire (Bactria) seceded as the Greco-Bactrian Kingdom, which had extensive contacts with India and China until its end in 125 BC. The Indo-Greek Kingdom, mostly based in the Punjab region but controlling a fair part of Afghanistan, pioneered the development of Greco-Buddhism. The Kushan Kingdom thrived across a wide swath of the region from the 2nd century BC to the 4th century AD, and continued Hellenistic and Buddhist traditions. These states prospered from their position on the Silk Road linking China and Europe.