When the prince had been gathering his army for his Spanish expedition, the lord of Albret had agreed to serve with a thousand lances. Considering, however, that he had at least as many men as he could find provisions for, the prince on 8 December 1366 had written to him requesting that he would bring only two hundred lances. The lord of Albret was much incensed at this, and, though peace was made by his uncle the Count of Armagnac, did not forget the offence, and Froissart speaks of it as the "first cause of hatred between him and the prince". A more powerful cause of this lord's discontent was the non-payment of an annual pension which had been granted him by Edward. About this time he agreed to marry Margaret of Bourbon, sister of the queen of France. The Black Prince was annoyed at this betrothal, and, his temper probably being soured by sickness and disappointment, behaved with rudeness to both D'Albret and his intended bride. On the other hand, Charles offered the lord the pension which he had lost, and thus drew him and his uncle, the Count of Armagnac, altogether over to the French side.