Though known by many different names in many traditions,But there is only one God. Krishna is the original person. The word Krishna means the person who is attractive to everyone.
Sri krishna appeared over five thousand years ago in Mathura,dist of state UP (India) to Devaki and Vasudeva in the jail of Kansa. Kansa was the king og mathura and mama ofthe loard krishna .The place of His birth is known as Sri Krishna JanmBhumi.
The Supreme Lord descends from time to time in this material world to reestablish the teachings of the Vedas. In His Bhagavad-gita, Sri krishna promises: "Whenever and wherever there is a decline in religious practice, O descendant of Bharata, and a predominant rise of irreligion--at that time I descend Myself. To deliver the pious and to annihilate the miscreants, as well as to reestablish the principles of religion, I Myself appear milleniumm after millenium."
Although eternal the Lord appears in specific circumstances out of mercy for His devotees. In fact, His principal biography, the Srimad Bhagavatam states, "the learned men describe the births and activities of the Unborn and Inactive." Therefore, although He appears within the material dimensions of time and space, He is most definitely not of it.
Historically, Sri krishna appeared on the midnight of the 8th day of the dark half of the month of Sravana. This corresponds to July 19th 3228 BC. He exhibited His pastimes for a little over 125 years and dissappeared on February 18th 3102 BC on the new moon night of Phalguna. (His departure marks the beginning of the current age of corruption known as Kali.)
The great scholar Srila Vishvanatha Chakravarti neatly outlines Sri krishna's activities in this way: the first three years and four months were spent in Gokula, then equal lengths of time in Vmdavana and Nandagram, eighteen years and four months in Mathura, and finally ninety-six years and eight months in Dvaraka totalling 125 years of manifest pastimes. See the Krishna-lila chart.