After the King of Qin had conquered the other six states, he called himself the First Emperor.
Tips
history
In Warring States stories 秦王 can be any king of Qin. The one 荆轲 tried to stab in 227 BC was 嬴政, the later 秦始皇; the one 蔺相如 made beat a 缶 at Mianchi was his great-grandfather, King Zhaoxiang.
culture
The Tang court dance 秦王破阵乐 ("The Prince of Qin Breaks the Enemy Lines") celebrated Li Shimin's victories as Prince of Qin.