Feeling that the siege was to be a close one, and knowing how much depended upon the issue, Sebastian lost no time in making every needful preparation for coming events.

The walls were strengthened everywhere; shafts were sunk, preparatory to the countermining operations which were soon to become necessary; the moat was deepened and cleared, and the forts near the gates were put in thorough repair.

On the other hand, Alexander had encircled the city, and had thrown two bridges, well fortified, across the river.

There were six gates to the town, each provided with ravelins, and there was a doubt in what direction the first attack should be made.
Opinions wavered between the gate of Bois-le-Duc, next the river, and that of Tongres on the south-western side, but it was finally decided to attempt the gate of Tongres.
Over against that point the platforms were accordingly constructed, and after a heavy cannonade from forty-six great guns continued for several days, it was thought, by the 25th of March, that an impression had been made upon the city.

A portion of the brick curtain had crumbled, but through the breach was seen a massive terreplein, well moated, which, after six thousand shots already delivered on the outer wall--still remained uninjured.