The baths were opened at sunrise and closed at sunset, but in the time of Alexander Severus, it would appear that they were kept open nearly all night, for he is stated to have furnished oil for his own thermæ, which previously were not opened before daybreak and were shut before sunset; and Juvenal includes in his catalogue of female immoralities that of taking the bath at night, which may, however, refer to private baths. The price of a bath was a quadrant, the smallest piece of coined money from the age of Cicero downward, which was paid to the keeper of the bath. Children below a certain age were admitted free, and strangers, also foreigners, were admitted to some of the baths, if not to all, without payment. The baths were closed when any misfortune happened to the republic, and Sentonius says that the Emperor Caligula made it a capital offence to indulge in the luxury of bathing upon any religious holiday. The baths were originally placed under the superintendence of the ædiles, whose business it was also to keep them in repair, and to see that they were kept clean and of a proper temperature. The time usually assigned by the Romans for taking the bath was the eighth hour or shortly afterward. Before that time none but invalids were allowed to bathe in public. Vilruvins reckoned the best hours adapted for bathing to be from midday until about sunset. Pliny took his bath at the ninth hour in summer and the eighth in winter; and Martial speaks of taking a bath when fatigued and weary at the tenth hour and even later. When the water was ready and the baths prepared, notice was given by the sound of a bell. One of these bells with the inscription Firmi Balneatoris was found in the thermæ Diocletiane, in the year 1548. When the bath was used for health merely or cleanliness, a single one was considered sufficient at a time, and that one only when requisite. But the luxuries of the empire knew no such bounds, and the daily bath was sometimes repeated as many as seven and eight times in succession. It was the usual and constant habit of the Romans to take the bath after exercise, and previous to the principal meal; but the debauchees of the empire bathed also after eating, as well as before, in order to promote digestion so as to acquire a new appetite for fresh delicacies. Nero is said to have indulged in this practice.