[MN 1158.] The martial disposition of the princes in that age engaged them to head their own armies in every enterprise, even the most frivolous; and their feeble authority made it commonly impracticable for them to delegate, on occasion, the command to their generals. Geoffrey, the king's brother, died soon after he had acquired possession of Nantz: though he had no other title to that county than the voluntary submission or election of the inhabitants two years before, Henry laid claim to the territory as devolved to him by hereditary right, and he went over to support his pretensions by force of arms. Conan, Duke or Earl of Britany, (for these titles are given indifferently by historians to those princes,) pretended that Nantz had been lately separated by rebellion from his principality, to which of right it belonged; and immediately on Geoffrey's death he took possession of the disputed territory. Lest Lewis, the French king, should interpose in the controversy, Henry paid him a visit; and so allured him by caresses and civilities, that an alliance was contracted between them; and they agreed that young Henry, heir to the English monarchy, should be affianced to Margaret of France though the former was only five years of age, and the latter was still in her cradle. Henry, now secure of meeting with no interruption on this side, advanced with his army into Britany; and Conan, in despair of being able to make resistance, delivered up the county of Nantz to him. The able conduct of the king procured him farther and more important advantages from this incident. Conan, harassed with the turbulent disposition of his subjects, was desirous of procuring to himself the support of so great a monarch; and he betrothed his daughter and only child, yet an infant, to Geoffrey, the king's third son, who was of the same tender years. The Duke of Britany died about seven years after; and Henry being MESNE lord, and also natural guardian to his son and daughter-in-law, put himself in possession of that principality, and annexed it for the present to his other great dominions.