The town was independent in the 13th century, but in 1353, owing to the dissensions of the Salvucci (Ghibellines) and Ardinghelli (Guelphs), it fell into the hands of Florence.
At this time the Ostrogothic kingdom, founded in Italy by Theodoric the Great, was shaken by internal dissensions, of which Justinian resolved to avail himself.
In his youth he was one of the infantes (princes) of Aragon who took part in the dissensions of Castile during the minority and reign of John II.
But dissensions arose between the German and Celtic elements of Civilis's following.
It was a step characteristic of his love for extreme and dramatic action, but it added to the dissensions between him and those who wished only for autonomy under the old dynasty, and his enemies did not scruple to accuse him of aiming at the crown himself.