A few years later, in 1191, the cathedral of Senlis was consecrated by that archbishop of Sens who was Philippe-Auguste's uncle, Guillaume of Champagne, William of the White Hands, the prelate who had completed the cathedral at Sens. And there came to the dedication Bishop Nivelon de Chérisy, just starting Soissons' Cathedral; Bishop Étienne de Nemours, at work on Noyon's; the prelate of Meaux, who was raising that cathedral; and many another expert in the new art. Sometime later, Bishop Geoffrey resigned his see, and in his place was elected Pierre Guérin, chancellor of France under three kings, a figure worthy to stand beside those Gallo-Roman bishops who remained as bulwarks of society when the Roman Empire fell in pieces around them.
Bishop Guérin was a man possessed by a passion for the public weal. His prudence and firmness caused Philippe-Auguste and Louis VIII to name him executor of their testaments. One of his enterprises was the organizing of the royal archives. It was he who came to Blanche of Castile to break the news of her husband's death as she rode out from Paris to meet Louis VIII returning from the southern war. For Louis IX during his minority he showed a father's affection. "He governed marvelously well the kingdom's needs," says the old chronicler, and when he died, on his grave they inscribed, "Here lies Guérin, whose life was an untiring work."
In early life Guérin had, in Palestine, become a Knight Hospitalier of St. John of Jerusalem, and, as bishop, continued to wear the white habit of that military order. At the battle of Bouvines, though not an actual combatant, he exhorted the troops and directed maneuvers, for he was skilled in the strategy of war. A survey of the enemy's position made him urge Philippe-Auguste to attack at once, and the king, who knew Guérin to be _sages homs et de parfont conseil_, obeyed, thus winning the greatest victory of the century. "On that day French unity received its baptism."
The king had vowed, were his arms successful, to endow an abbey. Bishop Guérin laid for him the first stone of the Abbaye de la Victoire, near his episcopal city.[52] Before this greatest of the bishops of Senlis died, his cathedral had begun to crown its southwest tower by the octagon and spire which are the boast of all the Valois country. St. Louis must have contributed to Senlis' famous tower, which places in foremost rank, this, the smallest cathedral in France. The unknown architect gathered features from many a beacon to unite them here in a masterpiece. He may be said to have created a new type, since his belfry at Senlis made a school in the region.[53]