After his return to Italy in 1220, Frederick spent most of the rest of his life there, with only two long spells away: one year on crusade (1228–9), and much of the years 1235–7 in Germany. No other ruler of Italy until modern times devoted himself to the affairs and problems of the whole peninsula with comparable zeal and intelligence. In the South, Frederick had little difficulty in restoring vigour to the monarchy, and his problems elsewhere did not noticeably weaken his regime in the kingdom. It remained loyal and was effectively managed by devoted public officials, promptly carrying out his instructions and constantly under scrutiny. But the kingdom could not preserve a splendid isolation from events elsewhere in the peninsula. Its regular government, its prosperity and its example made it the greatest ‘power’ in Italy, and it could not avoid the consequences. If it did not take the lead in the peninsula's affairs, it would be at risk from others.

Though Frederick could govern the kingdom in absentia, he may well have preferred to be there when he could, and only urgent business drew him away. In his favourite region of sojourn, Capitanata, it was easy to gather intelligence from Sicily on the one hand, and along the Adriatic coast into Lombardy and Germany on the other. Here, as early as 1223, he ordered a palace to be built at Foggia, and there he several times mustered impressive assemblies to discuss great matters of state.