The exact phrase was "veni, vidi, vici," which translates as "I came, I saw, I conquered," and was given in a message from Julius Caesar to the Roman Senate. It was apparently written in 46 B.C. in the city of Zela, which was located in the area now known as Tokat Province, in Turkey.
It was sent in order to inform Rome about his victory against Pharnaces II of Pontus, Caesar claims that the entire battle that he faced in Zela lasted only 4 hours and took place on the top of a hill where the Romans were situated. The Pontic forces were likely exhausted after the uphill march, and Pharnaces managed to escape.