It also served as a convenient fulcrum for the ambitious schemes of conquest which the princes of the House of Aragon in Spain began to entertain.

In territorial extent the kingdom of Naples was the most considerable parcel of the Italian community.

It embraced the whole of Calabria, Apulia, the Abruzzi, and the Terra di Lavoro; marching on its northern boundary with the Papal States, and having no other neighbors.

But though so large and so compact a State, the semifeudal system of government which had obtained in Naples since the first conquest of the country by the Normans, the nature of its population, and the savage dynastic wars to which it had been constantly exposed, rendered it more backward in civilization than the northern and central provinces.
The Papacy, after the ending of the schism and the settlement of Nicholas V.at Rome in 1447, gradually tended to become an Italian sovereignty.

During the residence of the Popes at Avignon, and the weakness of the Papal See which followed in the period of the Councils (Pisa, Constance, and Basel), it had lost its hold not only on the immediate neighborhood of Rome, but also on its outlying possessions in Umbria, the Marches of Ancona, and the Exarchate of Ravenna.