While fighting for the masters who offered him condotta in the complicated wars of Italy, Duke Frederick used his arms, when occasion served, in his own quarrels.  Many years of his life were spent in a prolonged struggle with his neighbour Sigismondo Pandolfo Malatesta, the bizarre and brilliant tyrant of Rimini, who committed the fatal error of embroiling himself beyond all hope of pardon with the Church, and who died discomfited in the duel with his warier antagonist.  Urbino profited by each mistake of Sigismondo, and the history of this long desultory strife with Rimini is a history of gradual aggrandisement and consolidation for the Montefeltrian duchy.

In 1459 Duke Frederick married his second wife, Battista, daughter of Alessandro Sforza, Lord of Pesaro.  Their portraits, painted by Piero della Francesca, are to be seen in the Uffizzi at Florence.  Some years earlier, Frederick lost his right eye and had the bridge of his nose broken in a jousting match outside the town-gate of Urbino.  After this accident, he preferred to be represented in profile—­the profile so well known to students of Italian art on medals and basreliefs.  It was not without medical aid and vows fulfilled by a mother’s self-sacrifice to death, if we may trust the diarists of Urbino, that the ducal couple got an heir.  In 1472, however, a son was born to them, whom they christened Guido Paolo Ubaldo.  He proved a youth of excellent parts and noble nature—­apt at study, perfect in all chivalrous accomplishments.  But he inherited some fatal physical debility, and his life was marred with a constitutional disease, which then received the name of gout, and which deprived him of the free use of his limbs.  After his father’s death in 1482, Naples, Florence, and Milan continued Frederick’s war engagements to Guidobaldo.  The prince was but a boy of ten.  Therefore these important condotte must be regarded as compliments and pledges for the future.  They prove to what a pitch Duke Frederick had raised the credit of his state and war establishment.  Seven years later, Guidobaldo married Elisabetta, daughter of Francesco Gonzaga, Marquis of Mantua.  This union, though a happy one, was never blessed with children; and in the certainty of barrenness, the young Duke thought it prudent to adopt a nephew as heir to his dominions.  He had several sisters, one of whom, Giovanna, had been married to a nephew of Sixtus IV., Giovanni della Rovere, Lord of Sinigaglia and Prefect of Rome.  They had a son, Francesco Maria, who, after his adoption by Guidobaldo, spent his boyhood at Urbino.

The last years of the fifteenth century were marked by the sudden rise of Cesare Borgia to a power which threatened the liberties of Italy.  Acting as General for the Church, he carried his arms against the petty tyrants of Romagna, whom he dispossessed and extirpated.  His next move was upon Camerino and Urbino.  He first acquired Camerino, having lulled Guidobaldo into false security by treacherous