of the Empire, but of which the greatest part had already been absorbed in the kingdom of France.
The Emperor's visit to the Pope, though only of ten days' duration, was, on the whole, successful, as he had obtained the Pope's promise to transfer the Holy See to Rome as soon as Charles should be able to enter Italy with an army, and protect the Pope against his enemies in that country.
On his return to Germany, Charles found that country so disturbed by internal dissensions, that he was not immediately able to fulfil his promise to the Pope. It was only in the year 1368 that Charles undertook a new expedition to Italy, where he first forced Bernabo de' Visconti, Lord of Milan, to sue for peace, and then marched to Rome to visit Pope Urban V, who had already arrived there the year before. Charles remained in Italy more than a year, but was recalled by threatening news from the East. King Louis of Hungary and King Casimir of Poland had entered into an alliance for the purpose of limiting what to them seemed the undue aggrandizement of the house of Luxemburg. They particularly wished to prevent the absorption of Brandenburg in the already extensive hereditary dominions of the Emperor Charles.
Margrave Otho of Brandenburg, son of the former German Emperor Louis and husband of Catherine, daughter
of the Emperor Charles, had ceded the succession to his margravate to his father-in-law, mainly on account of loans he had received from him. Otho, principally through the advice of King Louis of Hungary, now attempted to deny the validity of this engagement, and declared his nephew Frederick (son of his brother Stephen, Duke of Bavaria) his heir. Charles considered this violation of his pledge as a cause of war, and invaded Brandenburg (1371). After some fighting, Margrave Otho was obliged to submit, as he was insufficiently aided by the King of Hungary, and the death of King Casimir of Poland at this time frustrated all hope of help from that country. An agreement was arrived at (1373) through the mediation of the Pope—now Gregory XI. Otho renounced all his claims on Brandenburg, even during his lifetime, on payment of a large sum of money, and on the condition that the Emperor should
it came into the hands of the Emperor Conrad II, and henceforward formed a part of the Empire. As early as the thirteenth century parts of it fell into the hands of France" (Bryce, The Holy Roman Empire).
D