We must, therefore, bear in mind, first, that Wellington thought it likely that Napoleon would advance, if he advanced at all, by way of Mons, or to the westward of it, and, secondly, that he thought his own army was well placed to meet such an advance. In fact we may go further, and say that Wellington having this opinion about the line which the French would probably take, felt it all the more necessary to retain his troops in their existing positions, from which they could, as he judged, easily be assembled to meet such an attack, because he saw clearly that no assistance, certainly no immediate assistance, could be expected from the Prussians, in such an emergency, so remote were they from the Mons-Brussels route. If Napoleon was to be met or baffled in such a movement it must be by the Anglo-Dutch army. And the Duke also saw with equal clearness that nothing could serve the purpose of the French, if they were making their main attack by way of Mons, better than a premature movement of the Anglo-Dutch army towards Quatre Bras and Sombreffe, by which the communications of that army would be exposed throughout their whole length. Hence it was to be expected that the Duke would be most careful not to make such a premature movement, and, therefore, that he would insist on being convinced that the main French attack was by way of Charleroi before doing more than effecting the assembling of his scattered troops at their respective places of rendezvous. It so happened that the Prince of Orange, who commanded, as we have said, the 1st Corps, left his headquarters at Braine-le-Comte early on the morning of the 15th, rode to the outposts, heard some firing in the direction of Thuin, a village some ten miles west of Charleroi, and then rode straight to Brussels[152] without stopping on his way at his own headquarters. During his absence[153] reports had been forwarded to him from Generals Dörnberg and Behr, who were at Mons, to the effect that all was quiet in their front, and from Van Merlen, whose command lay a little to the eastward of Mons, that Steinmetz’s Prussian brigade had been attacked early in the morning[154] and that the enemy’s movements seemed to be directed on Charleroi. These reports remained some hours at the Prince’s headquarters, and were then forwarded to the Duke at Brussels, where they arrived in the evening. But before that time, in fact by or before 3 o’clock in the afternoon, the Prince himself had arrived, bringing his own report, which was a very indefinite one, and which was to the effect that the enemy had attacked the Prussian outposts near Thuin. This was the first information which the Duke received of the outbreak of hostilities.[155] About the same time, also, a dispatch[156] sent by Zieten to Müffling arrived, announcing that he had been attacked before Charleroi.