The battle was one of the turning points of the Hungarian War of Independence, being the decisive engagement of the so-called Gödöllő operation, and closing the first phase of the Spring Campaign.

After the Battle of Kápolna (26–27 February 1849), the commander of the Austrian imperial forces, Alfred I, Prince of Windisch-Grätz, thought that he had destroyed the Hungarian revolutionaries once and for all.

[3] Despite this he did not attack the Hungarian forces, as he lacked reliable information about the numbers facing him if he crossed the Tisza river and because of his caution, lost the opportunity to win the war.

At a meeting in Tiszafüred, they forced the Government Commissioner Bertalan Szemere to depose the Polish general and put Artúr Görgei in command.

This so infuriated Lajos Kossuth, the President of the National Defense Committee (the interim government of Hungary), that he wanted to execute Görgei for rebellion.

Schlik had wanted to obtain information for Windisch-Grätz about the positions and numbers of the Hungarian army and had moved towards Hatvan but was defeated there by the VII Corps and forced to withdraw without accomplishing his purpose.

[9] After the fighting on 4 April, Jelačić, the Ban of Croatia, claimed to Windisch-Grätz that he had actually been victorious, which misled the Field Marshal into ordering him to pursue the Hungarians.

[14] This forced a dilemma on Windisch-Grätz, to accept a battle where the Hungarians had superiority or to retreat to Pest, which was hard to defend, being open to attacks from three directions.

Being shallow, this creek usually did not represent an important barrier for anybody, but the heavy snowfalls and rains from the beginning of April 1849 changed this situation completely, making its banks marshy and its riverbed sludgy, which made its crossing very difficult, except through the bridges laying in Isaszeg, Gödöllő and at a couple of hundred meters north from the latter locality.

The wide vineyard on the northern end of Királyerdő, as well as the deer park southeast from Gödöllő, were also important natural shelters for the combatants on the left bank of the Rákos.

corps of Schlik was preparing for lunch when they heard the cannon fire coming from the south, and Windisch-Grätz saw an enemy column approaching from the direction of Aszód, so he ordered the Lobkowitz division to occupy their position east from Gödöllő.

[14] On 6 April Görgei gave orders for his troops to move and occupy the forming up points ready for the Hungarian attack due the next day.

Colonel György Kmety with a division to occupy Hévízgyörk, where they stumbled on Schlik's cavalry, composed by the Auersperg cuirassiers; after the Austrians retreated, the Hungarians halted.

[14] When the Zákó brigade approached the Királyerdő woods to 1500 paces, they heard the sounds of the shots from the north, signaling the start of the fight of Damjanich's troops with the enemy.

[27] But when the regrouped Bobich and Bátori-Sulcz brigades tried again to gain terrain outside the forest, the fire of the Croatian seressaners, positioned on the heights near Isaszeg prevented them to do this.

[28] Trying to take the initiative into their own hands, the Bobich brigade started an attack, but they were repulsed by the Austrian fire, which caused them to retreat, as well as the majority of Klapka1s troops, leaving important portions of the forest unprotected.

He then positioned his cavalry and his 4 batteries under Colonel Nagysándor between his corps and Klapka's, in the middle angle of the forest on a bare hill, engaging in an intense artillery duel with the Austrians.

[14] To make the situation even worse, Klapka gave the general order to retreat, but luckily Major Bódog Bátori-Sulcz, a man hard of hearing, understood quite the opposite, so he remained in his position.

[14] The Hungarians had hardly begun to advance when from their right side, from the vineyards between the lower mill and the Királyerdő his troops were hit by a tremendous cannon and rifle fire.

"White Feathered" battalion to chase out the Fiedler brigade from the northern section of the woods, but the fierce fight which ensued, momentarily none of the two sides was able to prevail.

Even though earlier he had received a message from Damjanich to hurry to the battlefield, Aulich, like Gáspár, insisted on obeying Görgei's orders of the day before to remain in position.

Only after the Chief of General Staff Lieutenant-Colonel József Bayer, hearing the sounds of the cannonade, ordered him to advance, did he finally depart with his troops towards Isaszeg.

[35] Then Görgei rode to the left flank and consulted with Klapka, who still wanted to continue his retreat, saying that his troops had run out of ammunition and were very tired, so "today it is impossible to obtain victory, but tomorrow it will be possible again".

The eventual arrival of Aulich's four battalions created confusion because the III Corps troops thought that they were Austrians and briefly opened fire, being stopped only by Damjanich's and Görgei's intervention.

This task was made impossible also by the numerical superiority of the Austrian cavalry, which had 34 squadrons against 17 on the Hungarian side, and by their artillery, as they had twice as many guns as Damjanich; on the right flank, excepting the successful resistance (as it was shown earlier) of the 3. battalion and the Polish legion against the renewed attacks of the Fiedler brigade, nothing, in particular, happened until around 11:00 p.m.[35] The 25th, 48th, 54th, 56th battalions of II Corps, together with III Corps, pushed the Austrians towards Gödöllő.

[14] After the battle of Isaszeg, the Hungarians sat camp around Gödöllő, being so confident of the effect of their victory on the Austrians, that they did not even deploy outposts to warn them in the case of a surprise attack by Windisch-Grätz's army.

[40] Although Kossuth was thinking about the declaration of independence for a while, the Hungarian victories which started on 2 April with the battle of Hatvan, culminating with Isaszeg, strengthened his determination that this was the right moment for this defining political act.

Also, the Battle of Isaszeg played a decisive role in Windisch-Grätz being relieved of command of the Habsburg armies by the emperor on 12 April, who named Feldzeugmeister Ludwig von Welden in his place, although until his arrival his duties were fulfilled by Josip Jelačić.

Also, his omission to send an order to Gáspár to attack with all his forces Schlik's corps prevented the Hungarian army to achieve an even greater victory.

While II Corps under Lajos Aulich remained in front of Pest, with the duty of misleading the Imperial forces, making such brilliant military maneuvers that the Austrian commanders thought that the Hungarian main forces were still in front of the capital planning to make a frontal attack against it, the I, III and VII Corps accomplished the campaign plan perfectly, and on 26 April relieved the fortress of Komárom.