during the 16th and 17th centuries these "autos" continued to appear, being gradually improved and elaborated until brought to their highest state of development by calderón. he has left about seventy "autos", the best known of which are "the divine orpheus", a work of considerable poetic merit, "the devotion to the mass", and "the captivity of the ark". his "autos" were the most popular and were the only autos performed in madrid from 1647 to 1681. these "autos sacramentales" produced a great effect on the people. from time immemorial, allegory of every kind had powerfully appealed to them, and these autos took a strong hold on the popular favor, coming as they did during religious festivals, with their music and their splendor, coupled with the fact that they were given at public expense and with the sanction of the catholic church.