But they were often also disruptive at court and occasionally proved threatening to the king. Their high birth not only attracted the king's attention, but sometimes drew the allegiance of frustrated noble courtiers, soldiers-of-fortune and henchmen, ambitious "bourgeoisie", malcontents and even provinces in search of a protector (e.g., the Neapolitan Republic) -- often against or in rivalry with the French Crown itself. Deeming themselves to belong to the same class as the king, they tended to be proud, and some schemed for ever-higher rank and power, or challenged the king's or parliament's authority. Sometimes they defied the royal will and barricaded themselves in their provincial castles (e.g., Philippe Emmanuel of Lorraine, duc de Mercœur), occasionally waging open war on the king (e.g., the La Tour d'Auvergne dukes of Bouillon), or intriguing against him with other French princes (e.g., during the Frondes) or with foreign powers (e.g., Marie de Rohan-Montbazon, duchesse de Chevreuse).