Tyrant (Gr. TUpavvos, master, ruler), a term applied in modern times to a ruler of a cruel and oppressive character. This use is, however, based on a complete misapprehension of the application of the Greek word, which implied nothing more than unconditional sovereignty. Such rulers are not, as is often supposed, confined to a single period, the 7th and 6th centuries B.C. (the so-called "Age of the Tyrants") of Greek history, but appear sporadically at all times, and are frequent in the later city-states of the Greek world. The use of the term "tyrant" in the bad sense is due largely to the ultra-constitutionalists of the 4th century in Athens, to whom the democracy of Pericles was the ideal of government. Thus the government which Lysander set up in Athens at the close of the Peloponnesian War is called that of the "Thirty Tyrants" (see Critias). The same term is applied to those Roman generals (really 18) who usurped authority locally under Gallienus.