An opportunity however soon offered for Theseus to do his country more essential service, and to acquire more illustrious fame. The Athenians, in a war with Minos, king of Crete, had been reduced to purchase peace of that powerful monarch by a yearly tribute of seven youths and as many virgins. Coined money was not common till some centuries after his age; and slaves and cattle were not only the principal riches, but the most commodious and usual standards by which the value of other things was determined. A tribute of slaves therefore was perhaps the most convenient that Minos could impose; Attica maintaining few cattle, and those being less easily transported. The burden however could not but cause much uneasiness among the Athenians; so that the return of the Cretan ship at the usual time to demand the tribute excited fresh and loud murmurs against the government of Ægeus. Theseus took an extraordinary step, but perfectly suited to the heroic character which he affected, for appeasing the popular discontent. The tributary youths and virgins had been hitherto drawn by lot from the body of the people; who might however apparently send slaves, if they had or could procure them, instead of persons of their own family. But Theseus offered himself. Report went that those unfortunate victims were thrown into the famous labyrinth built by Dædalus, and there devoured by the Minotaur, a monster, half-man and half-bull. This fable was probably no invention of the poets who embellished it in more polished ages: it may have been devised at the time, and even have found credit among a people of an imagination so lively, and a judgment so uninformed, as were then the Athenians. The offer of Theseus therefore, really magnanimous, appeared an unparalleled effort of patriotic heroism.