Michelangelo's most wilfully eccentric secular design was the Porta Pia (1561-1564). The function of this city gate was to terminate the vista from the Quirinal to the Aurelian walls down Pius IV's new street the Strada Pia, which was then lined with villas and gardens. In it Michelangelo combined elements of Medieval and Renaissance city-gate tradition with ideas derived from garden and festival architecture, as well as his own rich invention. Thus joky castellation, remnants of rustication and the Doric order are used as metaphors for strength, while the main portal evolved through a series of extraordinary drawings (Corpus, 614-621), superimposing and metamorphosing one solution over and into another. The result is a compendium of all the most fantastic elements of Michelangelo's architectural vocabulary-broken pediments, swags, masks, displaced fragments of the orders, overlapping planes and juxtaposed façades and profiles.