<P> The debt incurred during the war was gargantuan, approximately 4,200,000 florins . To pay, the state had to change the tax system . The current estimo system was replaced with the catasto . The castato was based on a citizen's entire wealth, while the estimo was simply a form of income tax . Apart from war, Filippo Brunelleschi created the renowned dome of the Santa Maria del Fiore, which astounded contemporaries and modern observers alike . </P> <P> The son of Giovanni di Bicci de' Medici, Cosimo de' Medici succeeded his father as the head of the Medici Bank . He played a prominent role in the government of Florence until his exile in 1433, after a disastrous war with Tuscany's neighbour, the Republic of Lucca . Cosimo's exile in Venice lasted for less than a year, when the people of Florence overturned Cosimo's exile in a democratic vote . Cosimo returned to the acclaim of his people and the banishment of the Albizzi family, who had exiled him . </P> <P> The Renaissance began during Cosimo's de facto rule of Florence, the seeds of which had arguably been laid before the Black Death tore through Europe . Niccolò Niccoli was the leading Florence humanist scholar of the time . He appointed the first Professor of Greek, Manuel Chrysoloras (the founder of Hellenic studies in Italy), at the University of Florence in 1397 . Niccoli was a keen collector of ancient manuscripts, which he bequeathed to Cosimo upon his death in 1437 . Poggio Bracciolini succeeded Niccoli as the principal humanist of Florence . Bracciolini was born Arezzo in 1380 . He toured Europe, searching for more ancient Greco - Roman manuscripts for Niccoli . Unlike his employer, Bracciolini also authored his own works . He was made the Chancellor of Florence shortly before his death, by Cosimo, who was his best friend . </P> <P> Florence hosted the Great Ecumenical Council in 1439; this council was launched in an attempt to reconcile the Byzantine Orthodox Church with Roman Catholicism . Pope Eugenius IV convened it in reply to a cry for assistance from the Emperor of the Eastern Roman Empire (also known as the Byzantine Empire) John VIII Palaiologos . John VIII's empire was slowly being devoured by the Ottoman Turks . The council was a huge boost to Florence's international prestige . The council deliberated until July 1439 . Both parties had reached a compromise, and the Pope agreed to militarily aid the Byzantine Emperor . Unfortunately, upon John VIII's homecoming to Constantinople, the Greeks rejected the compromise, leading to riots throughout what remained of the Byzantine Empire . John VIII was forced to repudiate the agreement with the Roman church to appease the rioters . As a result, no Western aid was forthcoming and the Byzantine Empire's fate was sealed . Fourteen years later in 1453, Constantinople fell to the Ottomans . </P>

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