The pride of the place was the library, a spacious square chamber in one of the rectangular towers that rose at each of the four corners of the castle. The floor was of coloured mosaics, figuring birds and beasts, the ceiling of ultramarine star-flecked in gold, and along the walls was ranged a collection of some nine hundred manuscript parchment volumes bound in velvet and damask, or in gold and silver brocades. Their contents contained all that was known of theology, astrology, medicine, music, geometry, rhetoric, and the other sciences. This room was the favourite haunt of the lonely, morose, and studious boy, the great Gian Galeazzo's younger son, Filippo Maria Visconti, Count of Pavia. He sat there now, by the log fire that hissed and spluttered and flamed on the cavernous hearth, diffusing warmth and a fragrance of pine throughout the chamber. And with him at chess sat the Lord Bellarion Cane, Count of Gavi, one of the new-found friends who had invaded his loneliness, and broken through the savage shyness which solitude and friendlessness had set about him like a shell. The others, the dark and handsome Countess of Biandrate, the fair and now almost ethereal Princess of Montferrat, and that sturdier counterpart of herself, her brother, were in the background by one of the two-light windows with trefoil arches springing from slender monials. The Princess was bending low over a frame, embroidering in red and gold and blue an altar-cloth for San Pietro in Ciel d'Oro. The Countess was yawning over a beautifully illuminated copy of Petrarch's 'Trionfo d'Amore.' The boy sat idle and listless between them, watching his sister's white tapering fingers as they flashed to and fro. Presently he rose, sauntered across to the players, drew up a stool, and sat down to watch the game over which they brooded silently. A crutch lay beside Bellarion, and his right leg was thrust out stiff and unbending, to explain why he sat here on this day of late December playing chess, whilst the campaign against Malatesta continued to rage in the hills of Bergamo. He was suffering the penalty of the pioneer. Having already demonstrated to his contemporaries that infantry, when properly organised and manœuvred, can hold its own in the field against cavalry, he had been turning his attention to artillery. Two months ago he had mounted a park of guns under the walls of Bergamo with the intention of breaching them. But at the outset of his operations a bombard had burst, killing two of his bombardiers and breaking his thigh, thus proving Facino's contention that artillery was a danger only to those who employed it.