war ended. 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. 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. 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. Few states could afford a large standing army, so permanent fortifications were intended to slow down an opponent, providing time to mobilise reserves. In 1672, the Dutch were nearly over-run due to the speed with which the French captured fortresses like Nijmegen, and saved only by activating the Hollandic Water Line. Van Coehoorn accepted the flat terrain of the Netherlands and huge cost of construction meant an effective defence could not rely solely on fortifications. His designs included these key principles; 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. 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"; 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