The feudal castle was built upon the plan of a triangle, with a tower
at each angle, the one at the apex being the _donjon_. The form of
this lofty keep is rectangular, and the machicolations and
embattlements which were added in the fifteenth century are in a
perfect state of preservation. Upon the platform, which I was able to
reach by means of ladders and the half-ruinous spiral staircase,
viper's bugloss spread its brilliant blue flowers over the dark
stones, and enticed the high-soaring bees. The view of the wide and
beautiful Dordogne Valley from these old battlements was not less
grand because more than one-half of the sky was of a bluish-black--a
mysterious canopy that concealed the genius of the storm, but from the
turbulent folds of which there darted every minute a dazzling line of
light. The tower on which I stood, although the highest of the three,
had never been struck by lightning, but one of the others had been
repeatedly struck, and the ruined masonry showed abundant signs of the
scorching it had undergone in this way. Lightning is capricious and
incomprehensible in its preferences.

This castle was besieged by Henry Plantagenet in 1159, but without
success. Subsequently he made another effort, and then reduced it. His
son Henry made it his headquarters for some time after he had
revolted. In 1369 Thomas de Walkaffera the English seneschal who held
Réalville on behalf of his sovereign, was besieged there by a Lord of
Castelnau, assisted by other barons. The garrison was overcome and
massacred. Another Lord of Castelnau, John, Bishop of Cahors, convened
a meeting of the States of the Quercy in his fortress, at which a
rising against the English was decided upon. It resulted in their
temporary expulsion from the Quercy.