The Duke of Wellington was informed, at Brussels, on the same day, of this attack of Napoleon on the Prussians at Ligny, and of the British advance, under the Prince of Orange, at Quatre Bras. It has been said that he was taken by surprise. Quite the contrary. He was waiting in the most suitable position for the movement of Buonaparte. This was announced to him by a Prussian officer of high rank, said to be Baron Müffling, who arrived at half-past one at his hotel in Brussels. Wellington immediately dispatched orders to all the cantonments of his army to break up and concentrate on Quatre Bras, his intention being that his whole force should be there by eleven o'clock the next night, Friday, the 16th. At three o'clock his Grace sat down to dinner, and it was at first proposed that notice should be sent to the Duchess of Richmond to put off a ball which she was going to give at her hotel that evening; but, on further consideration, it was concluded to let the ball proceed, and that the Duke and his officers should attend it, as though nothing was about to occur, by which the great inconvenience of having the whole city in confusion during their preparations for departure would be avoided. Accordingly, every officer received orders to quit the ball-room, and as quietly as possible, at ten o'clock, and proceed to his respective division _en route_. This arrangement was carried out, and the Duke himself remained at the ball till twelve o'clock, and left Brussels the next morning (April 16) at six o'clock for Quatre Bras. Such were the facts which gave rise to the widespread report that the Duke knew nothing of the attack of Napoleon till the thunder of his cannon was heard by the Duke of Brunswick in the ball-room.