The Cantelmoline linked the Isabella and Sint-Donaas forts. It was constructed as a continuous line with seven redans (bulwarks with two sloping sides), 150 metres from each other. Today the line is still clearly recognisable in the landscape. It owes its name to General de Cantelmo, the Spanish governor of Flanders, under whose governance it was rebuilt in 1640.
The Cantelmoline, constructed from 1632, replaced the Fontaine line or Linie van de Vuile Vaart from 1622. Today this is still visible in the landscape. Along both lines, a number of smaller redoubts were built; these have now disappeared.