COEHORN, Menno, Baron van (1641-1704), “the Dutch Vauban,” was of Swedish extraction, and was born at Leeuwarden, in Friesland. He served in the campaign of 1667 against Turenne, and later distinguished himself at the sieges, of Maestricht (1673) and Graave (1674), aud at the battles of Senef (1674), Cassel (1677), and St Denis (1678). The genius of Vauban had made a fine art of the attack and defence of fortified places, and Coehorn, who had already invented the mortar, had imposed on himself the task of meeting and beating that fine engineer on his own ground. But William of Orange did not recognize the abilities of his young captain, and in despair of success Coehorn had determined to transfer his services to France. William, hearing of this, seized the person of the engineer, and by a mixture of force and persuasion obliged him to renounce his design, and to accept a colonelcy in the Dutch service, with the command of two of the Nassau-Friesland battalions. The peace secured by the Treaty of Nimeguen (1678) gave Coehorn his first great opportunity. He repaired and perfected the defences of many strong places, and he rushed into polemics with a rival engineer, a certain Paen. His criticism and rejoinder appeared at Leeuwarden in 1682 and 1683, and in 1685 he gave to the world, in Dutch, his first great work, The New System of Fortification (Leeuwarden, folio), two French editions of which appeared in 1706, while three others were issued from the Hague in 1711, 1714, and 1741 respectively. From 1688 to 1691 Coehorn’s genius and activity answered the innumerable demands that were made upon them. In 1692 Vaubau himself laid siege to Namur, and Coehorn waited within the city. The town was reduced iu a week; but the castle in its quintuple enceinte, manned by ...