After a campaign of a few months, the Welsh gave in their submission to the king, and did homage for their territory. On the departure of the invaders, however, the mountaineers resumed their attitude of hostility, and made incursions into the surrounding country, at intervals, for many years afterwards. In consequence of his flight at the battle of Coleshill, the Earl of Essex was publicly accused of treason and cowardice by Robert de Montfort. The question was referred to a trial by arms, or a duel, between the accuser and the accused, in the presence of the king and his court. The Earl of Essex was defeated in the combat; but the king, instead of sentencing him to death, as was customary in such cases, contented himself with seizing the estates of Essex, and condemning him to pass the rest of his life as a monk in Reading Abbey. On the death of Geoffrey (1158) the city of Nantes fell under the authority of Conan, the hereditary Count of Brittany, who also possessed estates in Yorkshire, with the title of Earl of Richmond. Henry then set up a claim to the free city of Nantes, as a portion of the inheritance to which, as the heir of his brother, he was entitled. Actuated by the prospect of getting possession of the whole of Brittany, and affecting to regard Conan as a usurper, Henry confiscated his estate and title of Richmond. Then crossing the Channel with a large army, the king appeared before the walls of Nantes, and compelled the citizens to expel Conan, and to pay allegiance to himself. Henry then garrisoned the town with a body of his troops, and took possession of the rest of the country between the Loire and the Vilaine. [Illustration: HEROISM OF ST. CLAIR AT THE SIEGE OF BRIDGENORTH CASTLE. (_See p._ 182.)] Anticipating the alarm this great increase of his territory would cause in the French court, Henry sent there as ambassador Thomas Becket, and afterwards followed in person, and a treaty was concluded, by which the French king undertook to maintain his neutrality. Louis, after his divorce from Eleanor, had married Constance of Castile, who had borne to him a daughter. Henry affianced his eldest son to the young princess, who was delivered up to one of the Anglo-Norman barons, and her dower was confided to the custody of the knights of the Temple, to be restored on the celebration of the marriage.