Were the castles good for the English in 1086?

Answer 1

In 1086, or any year before about 1350, castles made good sense. The only ranged weapon was the longbow, and a strong stone wall with parapets could keep invaders out of the castle as long as there was food and water.

The advent of gunpowder and cannons changed everything. A couple of large cannon, dragged near the castle, could compel the defenders to surrender or be destroyed. Cannon fire could break down most average castle walls, and if the defenders didn't have cannon of their own, the outcome would be certain.

In the 1600s and later, newer "star fortifications" would be built allowing the defenders' cannon to be used to destroy an attacking army. But these "star forts", vaguely shaped like a 7-pointed star, didn't much look like a castle and were more like fortified cities.