During the Middle Ages, it was one of the most impregnable castles in Italy.

I had taken the impregnable castle, kept the bridge whole, pacified the men.

A man is shot and disfigured beyond recognition with a sawed-off shotgun in an impregnable castle, to which the only entrance is sealed.

The Lords of the Manor built an impregnable castle on a mound surrounded by marshland.

No one knew who had made this attack on the supposedly impregnable castle.

Denying their right to do so, he withdrew to an impregnable castle on the coast of Spain.

Built by Kobayakawa Takakage, an illustrious Japanese general, it was an impregnable castle.

Blade could not believe that the Emperor had built his impregnable castle with a tunnel running straight up into its heart.

Lombard historian Paul the Deacon mentions it in 611 as an "impregnable castle".

A long time ago, the West decided that there should be limits on the principle of a man's home being his impregnable castle.