The stadholder, at the head of a force of 17,000 infantry and 4000 horse, first made himself master of Venloo and Roeremonde and then advanced upon Maestricht.

Unfortunately before Roeremonde, Ernest Casimir, the brave stadholder of Friesland and Groningen, was killed.

He was succeeded in his offices by his son, Henry Casimir.

Arriving (June 10) before Maestricht, Frederick Henry proceeded to erect strongly entrenched lines of circumvallation round the town connecting them above and below the town by bridges.

Supplies reached him plentifully by the river.