What happened to Kashmir kingdom after the downfall of Kushans, Rajtanagni, the basic literary source of Kashmir, is once again silent about the emergence of the Kidera empire in Kashmir. However the archaeological and numismatic investigations under taken by the twenty century experts indicates that after the downfall of Kushans the Kashmir kingdom was under taken by the emperors of Kidera principality in about 380 AD.
Who where the Kideras? The historical records suggest that the Kidaras were also nomadic clan, believed to have originated in China and arrived in Bactria with the great migrations of the second half of the 4th century and encroached upon the Kushan empires which then comprised of Afganistan, now Pakistan, north western India and the parts of Jammu and Kashmir
They first entered Kabul and replaced the last of the Kushan rulers. They gradually took over the entire Kushan empire which had starched in west upto Kabul and in the east upto Varanasi.
According to the Chinese sources Kidarites appeared in Kazakistan and Bactria in 4th century and were branch of the Little Yuezhi. Some of them inherited the Kushan Empire and were called little Kushans.
The Kidarite kingdom was created either in the second half of the 4th century, or in the twenties of the 5th century.
The only 4th century evidence are gold coins discovered in Balkh dating from c. 380, where 'Kidara' is usually interpreted in a legend in the Bactrian language. Most numismatic specialists favor this idea. All the other data we currently have on the Kidarite kingdom are from Chinese and Byzantine sources from the middle of the 5th century.
They may have risen to power during the 420s in Northern Afghanistan before conquering Peshawar and part of northwest India, then turning north to conquer Sogdiana in the 440s, before being cut from their Bactrian nomadic roots by the rise of the Hephthalites in the 450s. Many small Kidarite kingdoms seem to have survived in northwest India up to the conquest by the Hephthalites during the last quarter of the 5th century.
The Kidara coins depict the motif of the standing king on obverse and seated goddess on reverse with legend in Brahmi letters Kidar shaha. Kidera issed coins in gold and copper. There gold coins are known from Kashmir as well. Few of the Kidera coins are also housed in the museums of Kashmir. In Kashmir their kingdom is believed to have been undertaken by Miherkula the leader of the Huns in about the concluding decade of 5th century AD.
Unfortunately the ancient period of the Kashmir history has not been explored in context of the available archaeological and numismatic sources. It is high time that a full-fledged research is under taken to reconstruct our ancient history.