Moreover, he then procured another grant[272] of the whole county of Cornwall, with the stanneries and mines, to be held of the king and his heirs by the service of two knights’ fees, bearing at that time the title[272] of Earl of Cornwall and Poictou. And before the end of that year, (viz. in the month of April,) the solemnity of the Feast of Easter being finished, took[273] to wife Isabell, Countess of Gloucester, widow of Gilbert de Clare, Earl of Gloucester, and sister to William Mareschal, then Earl of Pembroke; likewise the same year he obtained a grant[274] of the manor, castle, and honour of Knaresburgh, in com. Ebor. to himself and the issue of his body by the same Isabell, to hold by the service of two knights’ fees. Nor was he less eminent for his military knowledge than for those his great advancements in riches and honour; for in 20 Henry III. ambassadors from the Emperor came[275] to the king to desire that he might be sent to make war on his behalf against the French; but the king (though then married) having no child, answered,[275] that it could not stand with reason or safety that a person so young, and especially at that time being the heir apparent to the crown, should be employed on such an hazardous adventure, offering them the choice of any other. Nevertheless, before[276] the end of that year, this earl (with Gilbert Marshal, then Earl of Pembroke, and divers other great men) took[276] upon him the cross for a journey to the Holy Land; and for the better furnishing himself with money, sold many of his woods; but notwithstanding this resolution, he went not at that time, for the next year following, (viz. 21 Hen. III.) the king being seduced by the advice of aliens, and having wasted his treasure, required[277] a great supply from his subjects, which being granted and put into the hands of aliens to be transported, occasioned[278] high discontents; this earl, therefore, dealt freely with him, and represented to him the danger thereof; and though he found that what he then said availed little, ceased not the next year following to continue[278] his good advice, and in particular to tell him how ill he had done in permitting Simon de Montfort to marry the Countess of Pembroke his sister; which free and plain dealing with the king did not at all alienate his affections from him, for shortly after, viz. in 23 Hen. III. he obtained a grant[279] of the Castle of Lidford and Forest of Dertmore in fee; before the end of which year, meeting[280] with divers of the nobility at Northampton, they did there by oath oblige[280] themselves to go forthwith into the Holy Land for the service of God and the church.