When and why did the concentric castles change?

Answer 1

they changed to concentric casles so that enemies couldnt go underground and the whole castle would fall

Answer 2

Concentric castles wern't changed. They were changed fromthe motte and bailey castles.

Answer 3

They were built, to be better than the other castles and the truth is that they are the best protected castles that were built. :)

Answer 4

They changed from stone keep and improved to concentric castles

Answer 5

A natural extention of a stone keep castle.

Also siege warfare became more and more advanced, requiring more and more complicated defences, ie gunpowder was invented.

Answer 6

Square keep castles changed to concentric castles because castles got upgraded as we evolved, so did ideas for castles with more defence, space and attack power.

Answer 7

I dont now