On the night of the 13th of June, Zieten, who commanded the Ist Prussian Corps, and whose headquarters were at Charleroi, saw the French bivouac fires at Beaumont and Solre;[135] and, on the evening of the 14th, Blücher ordered the IId, IIId and IVth Corps to concentrate at or near Sombreffe. Zieten with the Ist Corps was to make as obstinate resistance as possible and fall back to and hold the village of Fleurus, thus gaining time for the concentration of the whole army.[136] These measures, it is admitted by all writers, were taken without any consultation being had with the Duke of Wellington at the moment. But it is claimed that there existed a definite understanding between the two commanders, in pursuance of which Blücher acted.[137] There had been a meeting between Wellington and Blücher at Tirlemont on May 3d, which the Duke[138] in a letter to the Prince of Orange pronounces “very satisfactory.” Baron Müffling, who was the Prussian military _attaché_ at the Duke’s headquarters, states[139] that the lines of march which the English and Prussian armies should respectively pursue _in case France should be invaded_, were definitely agreed upon and laid down in writing. This agreement may have been arrived at at that interview, though Müffling does not say so. He then goes on to say:—[140] “The junction of the English and Prussian armies for a _defensive_[141] battle * * * was so distinctly _prescribed by circumstances and by the locality_ that no doubt whatever could be raised on the point.” He then proceeds to give his views, and ends by saying:— “The point of concentration for the Prussian army was accordingly marked out between Sombreffe and Charleroi, and for the English, _en dernier lieu_, between Gosselies and Marchiennes.” We do not think[142] that Müffling intends here to state that Blücher and Wellington had made any agreement as to their respective action in case Napoleon should be the invader; he only tells us what in his judgment was the true course for them to take,—the course marked out, as he thought, by the circumstances and the locality. That we are right in this, will appear when the likelihood of Wellington’s having definitely agreed to advance his army to the very borders of the Sambre and the immediate vicinity of Charleroi, in view of his well-known anxiety for his communications, is considered for a moment.[143] We believe that the Duke, although doubtless informed of Marshal Blücher’s intention to concentrate his army at Sombreffe in case the enemy advanced by way of Charleroi, made no agreement whatever with him as to his own movements. The two commanders no doubt fully intended to act in concert, and expected and relied upon the hearty support of each other, but there was not, as we believe, any definite agreement as to the particular steps to be taken in the event of a French invasion.