The development of the political power of Florence, now fully conscious of its importance, was coincident with an increase in material wealth and with an awakening of intellectual life. Arnolfo had the good fortune to be born in the period when that great movement began, which, furthered rather than hindered by the animosity of civil strife, led to a remarkable revival in Italy of literature and art. It must be remembered that the way to it was paved by the age of the Hohenstaufen. The great poet who is so much identified with this eventful time[19] saw the foundations laid for the palace of the Signory and the new Cathedral, Sta. Maria del Fiore, Sta. Croce, and Sto. Spirito; he witnessed the construction of the Corn Exchange of Or San Michele, and the gloomy prison which still recalls the memory of party-strife.[20] In his banishment he thought of his beautiful San Giovanni, and in order to picture the steep ascent in Purgatory drew a comparison with the straight path, that now no longer exists, leading to the church of San Miniato, which looked down on the Rubaconte bridge, and commanded a view of the city.[21] Beside it in his time Bishop Andrea de’ Mozzi had begun to build the first embattled episcopal palace, which was completed by his successor, Antonio d’Orso, the same who instigated the populace to rise against the Emperor Henry IV. Dante was a witness of the indefatigable zeal with which corporation and citizens emulated each other in the erection of churches, great public buildings, the city-wall and defensive castles for the environs. No will was held valid unless a legacy was left by it towards the expenses of building the wall, while immunity from taxes was granted to the architect of the cathedral in gratitude for his excellent work. Benevolence had long been engaged in relieving human misery, and now with increase of means it was still more displayed. Folco Portinari, the father of him whose name has become celebrated far and wide through Dante Alighieri, founded the hospital of Sta. Maria, now one of the largest in any country, by extending a charitable institution commenced by Mona Tessa, a servant of his house. The corporation built the hospital at the Porto al Prato and took under their superintendence the one long since founded by a pious citizen at Porta San Gallo. The hospital of San Jacopo and that of Sta. Maria della Scala were annexed later. Contributions were everywhere given for churches and convents, for that of the Camaldulensians in the Angeli, the Servites in Cafaggio, the Silvestrines in San Marco, and others. An especial magistrate was appointed for the care of the streets and sewers, and the Carraia bridge was rebuilt.