Abstract
Marcus Tullius Cicero is known not only as orator an politician, but also as a philosopher. Especially in the late period of his life time he dedicated much of his time to study of Greek philosophy which became a great inspiration for his own philosophical works.
It was Greek philosophy that aimed Cicero´s attention to the idea of constant and perpetual rights of all humans for which he invented the term ius naturale. The term became frequently used by lawyers, thought other terms used in the similar sense may be observed in the works of the late republic and early principate, such as ius gentium and also aequitas