Who was the king in India 1400 years ago?
It's difficult to put a finger on the exact year for one and for the other, there was no India back then. Answering this based on the assumption that the OP is referring to the ruler of the landmass of modern India. The problem is that there were various rulers if you consider different parts of modern India.
Around the 6th century CE we see the decline of the Hephthalite (Eastern Huns) king Mihirakula. The Huns ruled from Persia to central India (with their capital as Bamiyan in modern Afghanistan). It is believed that Mihirakula's kingdom stretched upto Gwalior in central India. Though he was driven back to Kashmir by the Gupta king Narasimhagupta, the Guptas never regained their past glory.
At the eve of the 7th century, this is what India looked like.