After the sacking of Rome, in the 5th Century, the Ostrogoths took over. Under their rule, the city was constantly under attack from the Byzantines, who sent the population level below 1,000. The Lombards came to power in the 6th Century, ending the Byzantine assaults.
Florence grew to a population of 80,000 in the 14th Century, of which 25,000 were working in the wool industry. In 1378, a major revolt of the lower class led to the wool combers rising up and seizing the government of the city. Their progressive, radical democracy lasted for less than 2 months before the upper classes seized control once more, but the revolt so terrified the rich, that a century later it was still discussed in hushed tones much as the 1960s hippy movement is today.
The Albizzi family became the de facto rulers after the revolt. Worried about the rise of the Medici family, who were newly rich bankers rapidly gaining influence in Florence, Maso and Rinaldo Albizzi imprisoned Cosimo de' Medici and exiled him in 1433. But Cosimo gained influence behind the scenes, and rose to power in 1434, exiling the entire Albizzi family escept for Luca, who had been loyal to Cosimo. Luca Albizzi joined the Signoria, the ruling body of Florence, as Gonfaloniere, succeeding Cosimo's old friend Ilario Auditore in 1442.