Although the formsFirst Emperor,Shi Huangdi, andShih Huang-ti remain more common in non-scholarly English,秦始皇 is much more common in modern Chinese, with the non-truncated forms only appearing in scholarly or historical works.
The personal names嬴政 (attested since the Three Kingdoms period) and the rarehypercorrections趙政/赵政 (Zhào Zhèng) (attested since the middle Western Han) areanachronisms: Chinese of the period generally employed their姓 (xìng, “ancestral names”),氏 (shì, “clan names”), and名 (míng, “given names”) separately and not in the compound form of modern Chinese.
In historical context, referred to as秦王政 (Qínwáng Zhèng, “Zheng, King of Qin”) before his unification of China.