By midnight June 15th, 1815, the Duke of Wellington finally realized that he had been "humbugged" by Napoleon Bonaparte. Wellington had anticipated that Bonaparte would try to cut off his supply lines to the sea by swinging around his right flank at Mons.
He only found out that he was wrong when reports reached him via Prince William of Orange that the French had engaged a Prussian advance force at Charleroi and were driving them back towards Fleurus, south of Ligny.
Wellington's army was a mixed bag of forces, only about a third of which cane from Great Britain. The rest were from the Netherlands, Hanover, Nassau, and Brunswick.
That previous afternoon, still unsure of Bonaparte's intentions, Wellington had ordered his troops to begin concentrating. He ordered the Dutch portion of his army, his I corps under the Prince of Orange to concentrate around Nivelles.
But General Jean V de Constant-Rebecque, Prince William's Chief of Staff stationed at Genappe, only three miles from Quatre Bras, knew where Bonaparte was. He realized that this concentration order was a grave error. He decided to disobey orders and sent his available forces -- a brigade of the 2nd Netherlands Division -- south to occupy Quatre Bras ahead of the French.
Rebecque knew that Quatre Bras (meaning "four arms") was a strategic crossroads for both armies. If Wellington's army could hold it in strength, the Allies were in great position to support Blucher's Prussians. If however, the French could take it quickly, the Prussians would be isolated.
Wellington had pledged Blucher that he would support him insomuch as that was possible.
Now at midnight, realizing his mistake, he sent as many troops as he could towards Quatre Bras from Brussels to reinforce the Dutch.
Meanwhile, Napoleon had dispatched Marshal Ney with the left wing of his army northward towards Quatre Bras. Ney's orders were to hold the crossroads in strength, then send one division east to keep in contact with Marshal Grouchy who was to engage and hold down the Prussians on the right. After clearing away any Allied resistance, Ney was then to advance ten kilometers up the road towards Brussels. Napoleon would then join him with the reserve wing and then march on Brussels.
As it happened, Blucher decided to concentrate his force and stand and fight at Ligny. Napoleon's reserve wing participated in this battle.
Napoleon's communications with Ney had been spotty and muddled all day that 16th of June. There was a chance that Ney could attack Blucher's Prussians from the flank, if Ney was able to send troops in that direction from Quatre Bras.
Meanwhile Ney, unfamiliar with the commanders of his new command, decided to be cautious.
He sent a detachment of Lancers forward toward Quatre Bras to reconnoiter.
The light French cavalry encountered the Dutch covering force south of the crossroads and a skirmish ensued. The Lancers withdrew.
Ney now spent the morning massing his forces for a general advance. In the meantime, The Dutch were also reinforced.
The battle began in earnest at 2:00 pm on June 16th with the usual artillery barrage, followed by swarms of skirmishers preceding the advancing French columns.
The meager Dutch force at first gave way but rallied in some nearby woods. They were vastly outnumbered by French infantry and cavalry.
But then Wellington arrived with reinforcements, including some of his elite troops.
As the road towards Ligny was still open, Wellington rode off with his staff to arrange a pow wow with Blucher.
As Wellington returned from his meeting, more French troops arrived on the scene and threatened the Allied right flank.
But now the fighting became fierce all along the line. Parcels of land exchanged hands several times.
On two occasions, French cavalry caught Allied units in line before they could form square, severely mauling them. There was also an incident of "friendly fire" where Allied troops fired on their own cavalry because their uniforms were similar to that of some French cavalry.
The issue was in the balance. At 5:15 pm Ney learned that the French I Corps, without his knowledge, had begun a march eastward towards the fighting at Ligny. Fifteen minutes later, he received a vague order from Napoleon to seize Quatre Bras, then turn eastward to crush Blucher.
Ney could not do both at the same time. The issue was in doubt at Quatre Bras, so he ordered the I Corps to turn around and help with the battle at hand.
The battle remained in doubt. At one point Wellington himself was forced to take shelter inside a British square during a French cavalry charge.
But now Wellington received more reinforcements. At this point he actually outnumbered Ney.
Counterattacking, the Allies retook all of the ground that they had previously lost to the French. Things were looking up.
But now Wellington received word of Blucher's defeat and retreat from Ligny. This made his position at Quatre Bras untenable. Wellington was forced to withdraw.
By 9:00 pm the battle was over.
Casualties were heavy. The Allies lost 5,200 men, and the French 4,100. The battle was more or less a draw, but Napoleon still held the strategic advantage.
But Ney did not follow up aggressively. On the morning of the 17th, once Napoleon arrived, they followed Wellington at a leisurely pace allowing him to escape.
Napoleon had now decided to deal with Wellington. He ordered Marshal Grouchy with one third of the army to follow Blucher closely and prevent a link up with Wellington, while he would lead the main attack on Wellington himself.
It was raining heavily when Wellington finally stopped his retreat at a place that he had previously visited and "kept in his pocket".
He deployed his troops on a ridge line outside a farm by the name of Mont Saint Jean not far from the village of Waterloo.
