Menno van Coehoorn

Menno, Baron van Coehoorn (

Both had their advocates; Vauban's maxim of 'more powder, less blood' also took longer, an important consideration when most military deaths occurred from disease. He is also viewed as more innovative in the design and extent of his

However, unlike Vauban, Van Coehoorn had limited financial resources. He showed great skill in maximising these, while adapting to the specific challenges posed by the flat terrain in the Netherlands. Some of his water defences and designs were still being used in the 1950s.

Life

Van Coehoorn was born at

Van Coehoorn was educated at home with his brothers, and showed an aptitude for mathematics and military drawing. He later attended the University of Franeker, where he was supervised by his uncle Bernardus Fullenius (1602–1657), professor of mathematics and trainer of surveyors.^[2]

He had four surviving children from his first marriage to Magdalena van Scheltinga in 1678: Goosewijn (1678–1737), Gertruda (1679–1757), Hendrik (1683–1756) and Amalia (1683–1708). After her death in 1683, he married Truytje van Wigara (dates unknown); he died on 17 March 1704 and was buried at Wijckel.^[3]

Early career

In 1657, he was commissioned

In the Netherlands, 1672 is still known as the Rampjaar or Year of Disaster. The rapid fall of major fortresses like Nijmegen and Fort Crèvecœur near 's-Hertogenbosch demonstrated the Republic's vulnerability, and the obsolescence of its defences. This caused intense debate in two areas; first, where to locate strongpoints; second, how to design fortifications suitable to the flat terrain of the Netherlands.^[5]

Design principles

Van Coehoorn set out his ideas in a public debate over the design of a new fortress at Coevorden with Captain Louis Paen, an officer in the same regiment, who had produced a well-received critique of the Dutch drill manual in 1679.^[6] In 1682, Van Coehoorn published Versterckinge des Vijfhoeks met al syne buytenwerken or Fortification of the Pentagon and all its outer works; this was followed in 1685 by what remains his best-known work, Nieuwe Vestingbouw op een natte of lage horisont or New Fortress Construction on a Wet or Low Horizon.^[1]

Few states could afford a large standing army, so permanent fortifications were intended to slow down an opponent, providing time to mobilise reserves.

Active defence; defenders should constantly disrupt the besiegers, rather than simply sitting behind their walls. This meant providing open areas within the fortifications to assemble a counter-attacking force.^[8]

Multiple defence lines; the existing practice of all round defence meant a breach in one area often led to the rapid surrender of the whole position. Instead, Van Coehoorn created multiple 'Inner' and 'Outer' defence zones that funnelled attackers through successive 'killing zones' of flanking fire; Variously delivered from loopholed redoubts in the re-entrant places-of-arms, from earthen faussebrayes, and long, concave double-bastioned flanks. These works were screened from view by their low profiles, and, in the case of the flanks, by narrow, tower-like orillons of solid masonry";^[9]

Denial of terrain; "... he protected his works by digging alternate ranks of wet and dry ditches. The dry ditches and covertways were cut down to within a few inches of the water table ... (if the besiegers) cut into the floor in the normal way, they would soon be flooded out;"^[10]

Van Coehoorn argued the high water table common in the Netherlands negated the danger posed by mining, and thus he required only two-thirds of the materials needed for similar French fortifications.^[11] Water was another feature of his work; although completed years after his death, he designed the Zuider Waterlinie between Sluis and Nijmegen. His recommendation of a defensive barrier in the east, using the IJssel and the Dutch portion of the Lower Rhine, formed the basis of a NATO defence line built in the 1950s, codenamed Plans 'C' for Coehoorn and 'D' for Deventer.^[12]

Namur; the Sieges of 1692 and 1695

Nieuwpoort

Maastricht

Bergen op Zoom

Brussels

Liège

Charleroi

Namur

Huy

Mons

Ostend

class=notpageimage|

The Spanish Netherlands; key locations plus major Dutch sites

His ideas remained untested until the 1688-1697

Van Coehoorn was finally able to implement his ideas when appointed commander of Namur in 1691. Namur was divided between the 'City', on the flat northern bank of the river Sambre, with the 'Citadel' on high ground to the south controlling access to the rivers Sambre and Meuse. He strengthened the 'inner' Citadel with new outworks at Fort William and La Casotte, but did not have time to do the same for the 'outer' City area. The garrison of 5,000 was too small for an active defence, while many were poorly trained and motivated Spanish troops.^[14]

In the 1692 Siege of Namur, the City fell in less than five days, but the Citadel and its 500 Dutch defenders held out until 30 June. This was largely due to the terms negotiated when Van Coehoorn surrendered the City; he agreed not to fire on the City from the Citadel, in return for the French not attacking from that direction. As Vauban pointed out, this made it almost impregnable.^[14]

Regardless, the defence was a significant achievement and

The focus of the 1695 Allied campaign was the second Siege of Namur. The fortifications had been strengthened by Vauban, while Marshall Boufflers had a garrison of 13,000. Van Coehoorn was put in charge of siege operations and quickly captured the outer City; by mid-August, the Citadel remained largely intact and William was growing impatient. A battery of 200 guns was established and on 21 August began a continuous 24 hour bombardment of the Citadel's lower defences; assaults on the resulting breaches were extremely bloody, including 3,000 casualties in three hours on 30 August but the defenders surrendered on 4 September.^[16]

The two sieges of Namur were the key events of the Nine Years War in Flanders and made Van Coehoorn's reputation. Nieuwe Vestingbouw was translated into English, French and German among others and reprinted on a regular basis, while his ideas were widely used elsewhere, including

An often overlooked innovation used by both Vauban and Van Coehoorn was to focus their entire artillery on specific points, rather than the previous practice of targeting multiple areas. Overwhelming defences with massive firepower became known as the 'Van Coehoorn method'; Vauban preferred a more gradual approach, summarised as 'more powder, less blood.'[18] Both had their supporters; the trade off was time, an important consideration when far more soldiers died from disease than combat.^[19]

Later career

In recognition of his service, Van Coehoorn was promoted

Nijmegen and Bergen op Zoom were prioritised for upgrades, although both were incomplete when the War of the Spanish Succession broke out. Van Coehoorn was appointed Governor of Sluis and military commander in Zeelandic Flanders.^[22] The armies of the Nine Years War often exceeded 100,000 men, too large for the pre-industrial societies that supported them; Marlborough, Allied commander in the Low Countries, argued one battle was more beneficial than taking 12 fortresses.^[23]

Although Van Coehoorn agreed, the Dutch survived a century of almost constant warfare by keeping their army together; losing a battle might lose them the war, and they considered Marlborough's approach unnecessarily risky.^[24] Instead, they spent 1702 and 1703 taking towns such as Venlo and Roermond in the modern Dutch province of Limburg, as well as Liège, Bonn and Huy. Strategy was affected by conflicting objectives, between England and the Republic and also the States General. The States of Holland opposed the 1703 offensive against Ostend and Antwerp, since it potentially threatened Amsterdam's monopoly over the Scheldt river trade. In the confusion, a Dutch army was surrounded by a French force several times their size at Ekeren on 30 June, and only just escaped.^[25]

Rightly or wrongly, Van Coehoorn was blamed for this; he was a difficult character and William's death deprived him of his most powerful sponsor. The campaigns of 1702 and 1703 exposed his limitations as a field officer and led to criticism from Marlborough and his Dutch colleagues.^[26]

He was considering an offer to serve with the army of Savoy when he died on 17 March 1704 in The Hague, attending a conference with Marlborough. The States of Friesland paid for a monument over his grave at Wijckel.^[27]

Other

In May 1701, Van Coehoorn demonstrated a light-weight mortar to William, later known as the Coehorn (sic). Designed to provide cover for infantry assaults, it was first used at Kaiserworth in 1702 and variations remained in service during the US Civil War in 1861.^[28] He also led a number of significant civil projects, including re-dyking the Lower Scheldt, and designing new barrages along the Zuiderzee.^[29]

The Menno van Coehoorn Foundation was established in 1932 to preserve the cultural heritage of historical fortifications in the Netherlands and their associated wildlife.

His son Gosewijn Theodor van Coehoorn (1678–1736) wrote a biography of his father, The Life Of Menno Baron Van Coehoorn which is still in print.

References

Sources

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• Bromley, A.S., ed. (1970). The New Cambridge Modern History: Volume 6, The Rise of Great Britain and Russia, 1688-1715. Cambridge University Press.
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• Childs, John (1991). The Nine Years War and the British Army 1688-97: The Operations in the Low Countries. Manchester University Press.
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• van Coehoorn, M. (1685). Nieuwe vestingbouw, op een natte of lage horisont; etc. Hendrik Rintjes.
• van Coehoorn, Gozewijn Theodoor; van Sypesteyn, Willem Jan (1860). Het Leven Van Menno Baron Van Coehoorn (in Dutch). Kessinger Publishing Co.
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• Duffy, Christopher (1995). Siege Warfare: The Fortress in the Early Modern World 1494-1660. Routledge.
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• Eysten (1911). "Coehoorn (Menno baron van)". In P.J. Blok; P.C. Molhuysen (eds.). Nieuw Nederlandsch Biografisch Woordenboek. Deel 1 (in Dutch).
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• Lenihan, Padraig (2011). "Namur Citadel, 1695: A Case Study in Allied Siege Tactics". War in History. 18 (3): 282–303.
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• Lund, Erik (2002). Sandler, Stanley (ed.). Ground Warfare: An International Encyclopedia (Warfare Series); Volume I. ABC-CLIO Ltd.
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• Lynn, John (1999). The Wars of Louis XIV, 1667-1714 (Modern Wars In Perspective). Longman.
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• de la Colonie, Martin; Horsley, Walter (1904). The Chronicles of an Old Campaigner M. de la Colonie, 1692-1717 (2015 ed.). Scholars Choice.
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• Nolan, Cathal (2008). Wars of the Age of Louis XIV, 1650-1715: An Encyclopedia of Global Warfare. Greenwood.
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• Ostwald, Jamel (2006). Vauban Under Siege: Engineering Efficiency and Martial Vigor in the War of the Spanish Succession. Brill.
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• Van Hoof, Jaep (2004). Menno van Coehoorn 1641 - 1704, Vestingbouwer ~ belegeraar ~ infanterist (in Dutch). Instituut voor Militaire Geschiedenis.
• Van Nimwegen, Olaf (2010). The Dutch Army and the Military Revolutions, 1588-1688. Boydell Press.
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• Viganò, Marino (2007). Petrus Morettinus tribunus militum. Un ingegnere militare locarnese al servizio estero Pietro Morettini (1660–1737) (in Italian). Casagrande.
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• Young, William (2004). International Politics and Warfare in the Age of Louis XIV. iUniverse.

Wikimedia Commons has media related to Menno van Coehoorn.

• [1] Web page for the Menno van Coehoorn Foundation
• [2] Article on Coehoorn at fortified-places.com