Building the Kingdom examines how Giannozzo Manetti (1396–1459), by interpreting the great architectural projects of his day within historical, literary, and spiritual contexts, articulated their relevance for his contemporaries as cultural paradigms of the Early Italian Renaissance. Manetti, wealthy, learned, devout, and politically active, was perhaps the most admired lay thinker of his generation, a leader within the new intellectual currents of his native Florence and prominent in Rome at the court of Pope Nicholas V (1447–1455). Manetti’s detailed accounts both of the consecration of Florence Cathedral in 1436 (“De secularibus et pontificalibus pompis” [Concerning the Secular and Pontifical Parades]) and of the ambitious building projects planned by Nicholas for a revival of papal splendor in Rome (book 2 of his “Life of Nicholas V Supreme Pontiff”) are among the most elaborate architectural ekphrases of the fifteenth century. In these, he surpasses his better known rival, Leon Battista Alberti. These important Latin texts are presented here in new critical editions, with English translations and commentaries, preceded by chapters situating them within Manetti’s other writings, his vast reading, and his historical moment. A close reading of the texts, coupled with an in-depth examination of the sites described and the ceremonies conducted there, shows how Manetti’s distinctive fusion of Scholastic and Humanist ideas became authoritative for an Early Renaissance understanding of the cultural and spiritual power of buildings.