The prince and Peter then held a conference with Charles of Navarre at Bayonne, and agreed with him to allow their troops to pass through his dominions. In order to persuade him to do this, Peter had, besides other grants, to pay him 56,000 florins, and this sum was lent him by the prince. On 23 September a series of agreements were entered into between the prince, Peter, and Charles of Navarre, at Libourne, on the Dordogne, by which Peter covenanted to put the prince in possession of the province of Biscay and the territory and fortress of Castro de Urdialès as pledges for the repayment of this debt, to pay 550,000 florins for six months' wages at specified dates, 250,000 florins being the prince's wages, and 800,000 florins the wages of the lords who were to serve in the expedition. He consented to leave his three daughters in the prince's hands as hostages for the fulfilment of these terms, and further agreed that whenever the king, the prince, or their heirs, the king of England, should march in person against the Moors, they should have the command of the vanguard before all other Christian kings, and that if they were not present the banner of the king of England should be carried in the vanguard side by side with the banner of Castile.