[1][2] In 1250 the King, by putting strong pressure upon the electors, succeeded in obtaining[citation needed] the election of Aymer to the see of Winchester on 4 November.
However, he received confirmation of his election to the see from Pope Innocent IV on 14 January 1251, along with a dispensation to keep his other ecclesiastical income.
On 1 April 1258 Aymer sent a posse to attack men of the magnate John fitz Geoffrey at Shere in Surrey, killing one of them.
He was pursued to Winchester, besieged in Wolvesey Castle, and finally compelled to surrender and leave the kingdom.
[5] He was on his way back to England when he was overtaken by a fatal illness at Paris,[citation needed] having only been consecrated on 16 May 1260 before his death on 4 December 1260.