The creation of this one was a little interesting. There was no actual English text that spoke to me; so I went to Scotland's charters via the Records of the Parliaments of Scotland to 1707 website (http://www.rps.ac.uk/). The source text is a charter of James I of Scotland of 13 May 1426; its recounting of how the recipient had worked for various prior kings, those deeds having been confirmed by review of the "rolls of accounts" seemed precisely right for the situation. The original text was in Latin; I worked off of the transcription of the text and translated it from modern English into Middle English to fit Rowen's persona.
Edward Rex & Þyra Regina, to Owr Brigantia Herault: For as muche as owr rolles of accountes, diligently ouer-sayne & enspected by oure mandement, make fully clere to us þat in þe tyme of Kyng Gryffith of honourable memory, & of Kyng Lucan owr eldefader, & of Kyng Gregor, owr graunt-sire, & of wele belouyd Kyng Kenric, Kyngs of þe Este, owr illustres predicessours, Rowen Cloteworthy did fully, honourably, rightwisly & worshipfully serue þe Crowne of þe Este as Vox Regis Herault; & for as muche as þe aforeseyd servise is preysful & dere-worthy; þefor we ordeyne & comaunde ye, iustily & withoute delaiement, to graunt to þe sayde Rowen a Royalle Augmentacioun of Armes. In testificacion of which we send yow þis oure royalle chartre. Yeuen at Iron Bog upon þe Feste of Twelfþe Nyght, 5 Januarie, in þe first yere of oure reigne & in þe fourti-sefnthe yere of þe Sociate.
Þe which chartre havyng bene red fully, & þe resouns & instruciouns of þeir Majesties herd & understonden, I, Rian Brigantia, decree vnder þe grete seel of oure souerayne lorde & ladye þe present Kyng & Quene þat Rowen Cloteworthy schall beare and use in warr & peace hense foreward a Royalle Augmentacioun of Armes vpon þe termes aforeseyde.