Louis XIV of France sought to knock the Holy Roman Emperor, Leopold, out of the war by seizing Vienna, the Habsburg capital, and gain a favourable peace settlement.

Realising the danger, the Duke of Marlborough resolved to alleviate the peril to Vienna by marching his forces south from Bedburg to help maintain Emperor Leopold within the Grand Alliance.

A combination of deception and skilled administration – designed to conceal his true destination from friend and foe alike – enabled Marlborough to march 400 km (250 mi) unhindered from the Low Countries to the River Danube in five weeks.

After securing Donauwörth on the Danube, Marlborough sought to engage Maximilian's and Marsin's army before Marshal Camille d'Hostun, duc de Tallard, could bring reinforcements through the Black Forest.

The previous year had been one of successes for France and her allies, most particularly on the Danube, where Marshal Claude-Louis-Hector de Villars and Maximilian II Emanuel, Elector of Bavaria, had created a direct threat to Vienna, the Habsburg capital.

In the Dutch Republic, only a select few – Grand Pensionary Anthonie Heinsius, Simon van Slingelandt, Jacob Hop, and François Fagel – were privy to his strategy from the outset.

[15][d] Marlborough wrote to Godolphin: "I am very sensible that I take a great deal upon me, but should I act otherwise, the Empire would be undone ..."[16] In the meantime, the appointment of Henry Overkirk as Field Marshal caused significant controversy in the Dutch Republic.

On 14 May, Tallard brought 8,000 reinforcements and vast supplies and munitions through the difficult terrain, whilst outmanoeuvring Johann Karl von Thüngen [de], the Imperial general who sought to block his path.

[21] Encouraged by Marlborough's promise to return to the Netherlands if a French attack developed there, transferring his troops up the Rhine on barges at a rate of 130 km (80 mi) a day, the Dutch States General agreed to release the Danish contingent of seven battalions and 22 squadrons as reinforcements.

[22] On 10 June, Marlborough met for the first time the President of the Imperial War Council, Prince Eugene – accompanied by Count Wratislaw – at the village of Mundelsheim, halfway between the Danube and the Rhine.

Local German peasants, angry at French plundering, compounded Tallard's problems, leading Mérode-Westerloo to bemoan – "the enraged peasantry killed several thousand of our men before the army was clear of the Black Forest.

This had two aims: firstly to put pressure on Maximilian to fight or come to terms before Tallard arrived with reinforcements; and secondly, to ruin Bavaria as a base from which the French and Bavarian armies could attack Vienna, or pursue Marlborough into Franconia if, at some stage, he had to withdraw northwards.

[34] But this destruction, coupled with a protracted siege of the town of Rain over 9 to 16 July, caused Prince Eugene to lament "... since the Donauwörth action I cannot admire their performances", and later to conclude "If he has to go home without having achieved his objective, he will certainly be ruined.

Tallard preferred to bide his time, replenish supplies and allow Marlborough's Danube campaign to flounder in the colder autumn weather; Maximilian and Marsin, newly reinforced, were keen to push ahead.

A French reconnaissance under Jacques Joseph Vipart, Marquis de Silly went forward to probe the enemy, but were driven off by Allied troops who had deployed to cover the pioneers of the advancing army, labouring to bridge the numerous streams in the area and improve the passage leading westwards to Höchstädt.

[42][k] Marlborough quickly moved forward two brigades under the command of Lieutenant General John Wilkes and Brigadier Archibald Rowe to secure the narrow strip of land between the Danube and the wooded Fuchsberg hill, at the Schwenningen defile.

[58] Cutts' column – which by 10:00 had expelled the enemy from two water mills on the Nebel – had already deployed by the river against Blenheim, enduring over the next three hours severe fire from a six-gun heavy battery posted near the village.

Marlborough's anxiety was finally allayed when, just past noon, Colonel William Cadogan reported that Prince Eugene's Prussian and Danish infantry were in place – the order for the general advance was given.

As the attack faltered, eight squadrons of elite Gens d'Armes, commanded by the veteran Swiss officer, Béat Jacques II de Zurlauben [fr], fell on the English troops, cutting at the exposed flank of Rowe's own regiment.

[64] Marlborough, spotting this error, now countermanded Cutts' intention to launch a third attack, and ordered him simply to contain the enemy within Blenheim; no more than 5,000 Allied soldiers were able to pen in twice the number of French infantry and dragoons.

Count Horn's Dutch infantry managed to push the French back from the water's edge, but it was apparent that before Marlborough could launch his main effort against Tallard, Oberglauheim would have to be secured.

With their cavalry in headlong flight, the remaining nine French infantry battalions fought with desperate valour, trying to form a square,[85] but they were overwhelmed by Blood's close-range artillery and platoon fire.

"[85] The majority of Tallard's retreating troops headed for Höchstädt but most did not make the safety of the town, plunging instead into the Danube where over 3,000 French horsemen drowned;[q] others were cut down by the pursuing Allied cavalry.

Then, declaring in disgust that he wished to "fight among brave men and not among cowards", Prince Eugene went into the attack with the Prussian and Danish infantry, as did Leopold I, waving a regimental colour to inspire his troops.

Lord John Hay and Charles Ross's dismounted dragoons were also sent, but suffered under a counter-charge delivered by the regiments of Artois and Provence under command of Colonel de la Silvière.

[99] Orkney, attacking from the rear, now tried a different tactic – "... it came into my head to beat parley", he later wrote, "which they accepted of and immediately their Brigadier de Nouville capitulated with me to be prisoner at discretion and lay down their arms."

Pausing for a moment, he scribbled on the back of an old tavern bill a note addressed to his wife, Sarah: "I have no time to say more but to beg you will give my duty to the Queen, and let her know her army has had a glorious victory.

"[105] Although the war dragged on for years, the Battle of Blenheim was probably its most decisive victory; Marlborough and Prince Eugene had saved the Habsburg Empire and thereby preserved the Grand Alliance from collapse.

[104] Despite being offered the chance to remain as ruler of Bavaria, under the strict terms of an alliance with Austria, Maximilian left his country and family in order to continue the war against the Allies from the Spanish Netherlands where he still held the post of governor-general.

"[111] The military historian John A. Lynn considers this claim unjustified, for King Louis never had such an objective; the campaign in Bavaria was intended only to bring a favourable peace settlement and not domination over Europe.