All Saints’ Day is November 1st—someone must have misread the number. I don’t know if they would be using Arabic numerals this early (where it would be easy to misread a 1 as a 7).
Is it possible that the discrepancy is due the difference between the Julian and Gregorian calendars?
The document was written a week after the Feast of All Saints. Here is the Latin and the translation from the National Archives:
Ph[ilippus] dei gra[tia] Franc[orum] Rex dil[ec]tis et fidelib[us] gentib[us] n[ost]ris ad Roman[am] Cur[iam] destinatis, s[a]l[u]t[em] et dil[ectionem]. Mandam[us] vob[is] quat[enus] Sum[m]um Pontificem requiratis ut dilectum n[ost]r[u]m Guill[el]m[um] le Walois de Scotia militem reco[m]mendatum habeat in hiis q[ue] ap[ud] eum habu[er]it expedire. Dat[um] ap[ud] Petrafontem die Lun[e] post festum Omn[ium] Sanctor[um]. [Endorsed]: Quarta l[itte]ra R[egis] Franc[ie].
Philip by the grace of God, king of the French, to his beloved and loyal people appointed at the Roman Court, greetings and favour. We command you that you ask the Supreme Pontiff to consider with favour our beloved William le Wallace of Scotland, knight, with regard to those things which concern him that he has to expedite. Dated at Pierrefonds on the Monday after the feast of All Saints [7 November 1300]. [Endorsed]: Fourth letter of the King of France.