​How Marlborough used rivers to support his victories in Belgium

River running through countryside
Join our expert-led history holiday, Marlborough's Victories in Belgium, and you'll visit some of the rivers that were crucial to his strategy. Here we look at how the great commander used waterways to defeat his French foe.

One of the striking things about rivers is that they largely stay in the same place they have always been. Unlike roads which can be new, motorways and by-passes, rivers are generally the same shape and route they have always been for hundreds of years. 

Some have been ‘improved’, dredged, straightened, canalised, but for students and aficionados of the 17th and 18th centuries, when we look at a river today, we are essentially seeing the same attributes and challenges a general would have contemplated 300 or more years ago.

Marlborough understood how rivers could aid troop movement in Belgium

We can picture John Churchill, 1st Duke of Marlborough at his country house ‘Holywell’ in St Albans with the rudimentary (to our modern eyes) maps of the 1690’s and 1700’s, spread out on the table before him. 

He looks out onto his orchards. Gardeners are tending to the flower beds laid out in the Dutch style reflecting the fashion brought across by King William and his court after the Glorious Revolution in 1688.

A long pool of water – a canal- runs down the far side of the garden. It is ornamental- but a key feature of the Dutch style. Water. The Dutch know a lot about water and are experts in its use and manipulation. 

How to use rivers to achieve your campaign goals was a fundamental skill required in a successful Army general in the wars of the League of Augsburg (1688-1697) and the Spanish Succession (1701-1713).

Unsurprisingly, the most prominent feature on the maps in front of Marlborough were the rivers. They could provide the means of moving troops and materiel. 

The were the transport arteries that would enable his campaign to succeed. Hills were exaggerated, forests enlarged, but the drawn rivers showed exactly where they flowed.

When Marlborough looked at the map of Flanders, or the Spanish Netherlands as it was then, there are several mighty rivers that set out the parameters, the borders for any campaign. 

Control of rivers was vital 

The Rhine, the Meuse, the Moselle, the Scheldt, the Dender, the Sambre – and when planning his campaigns he could see how his prime enemy, France, would always be advancing North and up those river valleys… the direction of flow of these rivers was always signalled on these ancient maps by a helpful arrow with a bulbous base! 

17th century maps were designed to simply show routes from one location to another, not to provide a detailed representation of a landscape. That would take another 150 years to come about.
So control or use of the rivers was probably the most important consideration a commander would have in setting out his plans for the forthcoming campaign season. 

He would need to know where the bridges were, the fords, the best places to site a pontoon bridge. 

He would have to have some idea of the rate of flow of the river and whether it could be safely crossed by a huge army over several hours. 

So rivers were boundaries, obstacles, defensive frontiers that could be used to protect an army or an encampment in those days of manoeuvre. 

Click here to discover our four-day tour of Marlborough's Victories in Belgium, led by expert James Falkner. 

Marlborough was an unconventional commander

In Marlborough’s time, there was always a preference from the politicians back home both in the Hague and London to gain ground by outwitting an enemy in manoeuvre across landscapes and besieging a town that ‘controlled’ the surrounding fields and villages and river. 

Safer this than to risk all in a field of battle where an army could be wiped out or a campaign lost in a single day – as certainly happened to the great enemy France at Blenheim, Ramillies and Oudenaarde. 

Unconventionally, Marlborough always sought confrontation in the field.

Rivers also provided internal lines. If you wanted to move equipment and men quickly to secure a town or new territory, a river provided that means efficiently and cheaply. 

Marlborough is famous for many things – but at least two of his chief characteristics were his desire always to bring the enemy to battle in the field – rather than besiege a force in yet another town – and second his consideration for his troops to make sure they were fed and supplied and that they did not have to rely on devastating the local populace to find food or shelter (unlike other armies of the period). 

Marlborough's march to the Danube

So the route and flow of rivers, their bridges, towns, crossing places and fords would dominate the planning and thinking of any worthwhile commander at the start of a campaign season. 

Where there were bridges or convenient crossing places then communities and settlements grew up around that trading point. And then walls and defensive works were built to defend those very bridges and towns.

Marlborough followed the lines of rivers on his famous march to the Danube valley in May 1704. 

This forced river-march, prevented the French invasion of the Imperial lands and an attack on Vienna, and culminated in the great victories at the battles of Donauworth and Blenheim. 

First Marlborough followed the Rhine, then the Neckar, then across country to the river Danube and the town of Augsburg. 

Then, having been joined by his famous ally Prince Eugene, he advanced up to the walled town of Nordlingen and then besieged the Schellenberg, a fortress left over from the bloody Thirty Years War alongside the river town of Donauworth. 

Finally he advanced his multi-national confederate forces onto the plain to the East of Hochstadt – with the little Nebel stream in front of him and the winding Danube to anchor his left wing by the village of Blindheim - and began to attack the encamped French Army who had been caught completely by surprise.

Marlborough man of action

Marlborough may have been dyslexic – not a recognised condition in the early 1700’s. This may account for the paucity of written communication from him- compared with other authors of the period – despite the fact that he wrote or dictated field reports every night whilst on campaign and wrote personal letters to his wife Sarah every day when he was abroad. 

This was an Age of many pamphlets and early newspapers and scandal sheets, all designed to acquaint the population back home with what was happening in far off Europe or more often to push a particular Whig or Tory viewpoint or philosophy. Politics was often conducted in print and in the coffee houses of London. 

But Marlborough was not a fan of writing or indeed reading.  

He was a man of action. He wanted to be on the spot, see for himself. 

He was no armchair general. 

What he did possess was a great sense and eye for the ‘lay of the land’. 

He was a master of manoeuvre of course and knew the Spanish Netherlands like the back of his hand by the time he had finished campaigning. He always kept a landscape or a field, a terrain or a range of hills ‘in his pocket’ for future reference – a place where he knew one day he could bring the enemy to battle. 

He engineered this at Elixhim, Ramillies and Malplaquet. 

One hundred years later, Wellington had a similar aptitude for understanding the landscape he was viewing and with intelligent anticipation, both men were able to work out how long it would take to march troops from A to B, or the killing range of a battery mounted on an outcrop. 

This understanding came from their deep study of available maps, where the rivers flowed and the towns were built – and the desire they both shared to always know what was on the ‘other side of the hill…’ 

Keeping armies on the move

Logistics and supply are crucial to the performance of an Army. 

If the clothes, shoes, food etc are not in the right place at the right time, the troops will suffer and morale will fall. 

And Marlborough always wanted to keep the army moving – each campaign had a clear purpose and objective.

Marlborough always had a strong sense of the need to maintain morale by feeding his army well and making sure that bread and beer were available whenever they were required. 

This meant planning and forward-thinking. 

Cadogan, Marlborough’s Quarter-Master General as well as deputy and counsellor (especially in the absence of Prince Eugene) was a very effective administrator and negotiator. 

He made sure that supply depots were in place along the river-routes that Marlborough had selected for his campaigns. 

Flanders was rich in its numbers of canals and rivers which enabled the transport of goods. So controlling access to these water courses would always be a key campaign objective. 

The people of the Dutch republic and northern Spanish Netherlands knew how to control and use water, they could flood fields and open sluice gates to prevent enemy army movements. 

The Dutch and the north Belgians (as they are today) had a deep understanding and ‘feel’ for the multiple uses of water. 

Water was not the enemy. 

Water was their friend.

The deceptive Quarter Master General

As Quarter Master General, Cadogan had the task of setting up the supply bases over Winter, ahead of the next campaign season. 

Cadogan ran a network of informants, individuals who were paid to report on enemy troop movements or the plans of major personalities – friends and foes alike. 

It was his experience of ‘running’ this network that allowed the QMG to negotiate and put in place the supply depots required for the coming fighting season. 

Cadogan was adept at deception too. 

There was also ‘interest’ for himself and his master in all the dealings (with public money) that went on to secure Army supplies. 

He would arrange supply bases in many locations so that no-one could guess in which direction Marlborough would advance. 

One fact each year in their favour, was that the enemy was always coming up from the South – invading mostly North and East, wanting to extend the footprint of France in a land-grab demanded by the ambitious and covetous King Louis XIV. 

The rivers in the Spanish Netherlands and Northern France helpfully spread themselves like fingers on a grasping hand from their springs and sources in the higher grounds of Picardy and Flanders. 

Then they broaden and deepen into the open along the coastal plains of the Spanish Netherlands and then on, on their journey to the sea, the North Sea, and that is where they mostly end in estuaries and deltas.

Marlborough innovated to challenge conventions

The Lys, the mighty Scheldt, the Dendre, the Senne, the Dyle and the Gheete – and all their tributaries were the perfect ‘motorways’ for transporting goods of all kinds as well as infantry and cavalry. 

The large pontoon trains that accompanied the early 18th century armies made it clear how important the negotiating of a river may become – in any campaign or conflict.
The floating barge illustrates the ingenious thinking and planning of the commanders of that time- making use of all local natural resources to achieve their objectives. 

If you want to move a cavalry regiment, why not put horses and men on a barge? 

Rivers and water courses are crucial in planning a campaign. 

They are the arteries, the blood vessels that can help an army move swiftly and efficiently from one place to another. 

Marlborough was always very conscious of speed. 

This was manoeuvre warfare and clearly there was an expected timetable of events. 

Like all innovators, Marlborough challenged existing conventions. 

This made him unpopular in some places but also unpredictable and successful and admired by his enemy in France and his allies in Europe – if not increasingly by the opposition and court at home. 

Help from the Devil

A marching army would break camp and leave long before sunrise to avoid the hottest time of day and would arrive at its new encampment before lunchtime and would spend the rest of that ‘day’ pitching tents and cleaning weapons and clothes and resting before the next march.

On the way to Oudenaarde, Cadogan raced his advance guard to the river Scheldt – so that he was on the heights of Eename even before the French army across the river, had woken up for the day.  

‘The devil must have aided them’ said one French General when he learnt where the British were. 

Cadogan quickly set about building his five pontoon bridges across the fast-flowing Scheldt, so that when his Commander arrives a few hours later with the main body of the army they were able to cross here rather than through the constricted and crumbling narrow streets of the town of Oudenaarde itself.

The battle of Oudenaarde

In that year, 1708, the slow-moving and quarrelling French had succeeded in unbalancing Marlborough whose prime objective had been to cover Brussels from attack, and the French had captured the towns of Bruges and Ghent and thereby all the land west of the River Scheldt. 

Only the town of Oudenaarde remained defiantly with the allies, and its loss would have cut Marlborough off from the coast and his English supplies. 

The wide and powerful River Scheldt heading down from Antwerp almost North-South into France had become a frontier -with the French to the West and the Allies on the East and Brussels side. 

It was a major obstacle that would have to be crossed by 80,000 men and equipment if Marlborough were to achieve his annual objective of taking the fight to the enemy and engaging them in battle. 

When Prince Eugene rejoined Marlborough after a long march up from the river Rhine, Marlborough’s chutzpah and confidence returned (after a long period of illness and headaches) and he was ready for the fight.

Victory of course followed in the stunning outcome at the battle of Oudenaarde in July 1708. 

Once again, Marlborough’s army had to cross a wide river in order to engage the French Army. 

They had felt secure behind the ‘river barrier’. 

The speed, aggression and unconventionality of Marlborough and Cadogan (who often led the Advance units) were regularly underestimated by the French – despite their experiences of recent years, and their sneaking admiration for the British general.

In the military campaigns in Flanders in the late 17th and early 18th century, the role and position of rivers, canals and water courses was crucial. 

The site and shape of these features in many ways dictated tactics and campaign objectives – far more so than other geographic features. 

Marlborough had begun his career in the household of James, brother of King Charles. Both these men were avid sailors and James became Admiral of the Navy. 

Marlborough himself was never a good sailor. He was frequently seasick on his many crossings from Harwich to Hellevoetsluis to conduct campaigns or diplomacy in Flanders or the Hague. 

But he never underestimated the importance and value of rivers and water in achieving his goals. 

He studied them well. 

To find out more about Marlborough's mastery of the waterways, join our tour Marlborough's Victories in Belgium, led by James Falkner, and expert on the War of the Spanish Succession. 


  • Chandler David G, The Art of warfare in the Age of Marlborough, 1990
  • Coxe W, Memoirs of John Duke of Marlborough, 1848
  • Churchill W, Marlborough: His Life and Times, 1934
  • Falkner James, Great and Glorious Days, Marlborough’s battles 1704-09, 2002
  • Falkner James, Marlborough’s Wars – Eyewitness Accounts, 2005
  • Falkner James, Marlborough’s War Machine, 2014
  • Field Ophelia, The Kit-Kat Club, 2009
  • Hussey J, Marlborough: Hero of Blenheim, 2005
  • Lediard T, Life of John, Duke of Marlborough, 1736
  • Watson, JNP Marlborough’s Shadow, 2003
More articles about Marlborough in Flanders on Promenades Travel:
>> VIDEO: Marlborough, the Great Commander
>> Malplaquet: the bloodiest battle of the 18th century
>> The Battle of Blenheim: France's invincible army defeated
>> Oudenaarde: a triumph for Britain's bold commander
>> Marlborough specialist talks history, tours and the thrill of being "there"
>> Marlborough in Ireland: the making of England's great military leader
>> A sense of place: James Falkner
>> A reading list for Marlborough's Victories in Belgium