We are told that in every spot in Roman Alexandria one was bound to come upon a group of noisy and disrupting Cynics, "bawling out the usual street corner invocations to Virtue in a loud, harsh voice, and abusing everyone without exception," as Lucian describes them (The Passing of Peregrinus 3).
Navia, Luis E. Classical Cynicism : A Critical Study. Westport, CT: Greenwood Press, 1996.
Classical Cynicism was a philosophical movement from the beginning of the fourth century B.C. until the fall of Rome. Rather than a 'school' of philosophy, it was an informal group of philosophers with certain attitudes and unconventional behaviors who either called themselves Cynics or were so-called by others.
The first Cynic was Antisthenes, an associate of Socrates. The most recent was Sallustius, in the fifth century. In between were, among others, Diogenes of Sinope, Crates of Thebes, Hipparchia and Metrocles of Maroneia, Monimus of Syracuse, Menippus of Pontus, Bion of Borysthenes, Cercidas of Megalopolis, Meleager and Oenomaus of Gadara, Demetrius of Rome, Demonax of Cyprus, Dio Chrysostom of Prusa, and Peregrinus Proteus.
Cynics sought to attain arete (Greek) or virtus (Roman), a quality we very imperfectly translate "virtue." This virtus is the strength to overcome one's thoughts, feelings, and the circumstances of one's life. Because this virtue was their goal, Cynics disregarded social conventions and appearance.