King Otto IV confirms the Duchy of Bavaria to Duke Ludwig of Bavaria and his heirs, bestows upon the same duke the farm of Mering with income of 200 marks, and the imperial fiefs of the murderers of Philip of Swabia - Count Palatine of Bavaria Otto VIII of Wittelsbach and Henry IV of Andechs, the margrave of Istria - including the Margraviate of Istria.
‡Otto‡ quartus Dei gratia Romanorum rex et semper augustus.
Notum facimus ętati presentium et posteritati futurorum Christi fidelium quod nos, inspecta devotione quam circa promotionem nostram illustris vir Lodewicus dux Bawarorum fidelis et dilectus noster erit omni tempore habiturus, regia munificentia donamus et presentis paginę privilegio confirmamus, tam ipsi quam universis sibi successuris heredibus, Ducatum Bawarię cum universis terris et possessionibus quas idem dux adhuc vivente antecessore nostro in manu sua et possessione tenuit, tam cum hominibus quam cunctis eis pertinentibus.
Insuper concedimus eisdem curtem Moringen, quę olim illustrissimi genitoris nostri extitit, cum pertinenciis eius et partem illam quę contingit filias quondam Ph[ilippi] regis, simul eidem duci et heredibus suis tradimus et donamus per excambium vel alio quolibet modo disposituri, quod dictę regis filię nominatam hereditatis suę porcionem grato assensu in manus nostras resignabunt.
Sic quoque dispositum est et statutum, ut dictus dux cum curte memorata a nobis teneat ducentas marcas in liberis reditibus, et si de hac summa quicquam defuerit, nos de aliis reditibus nostris in Bawaria defectum illum supplebimus. Si autem in bonis ipsis aliquid de summa prescripta superfuerit, illud in nostros usus cedet et cum fratribus nostris H[einrico] palatino comite Rheni et W[ilhelmo] duce taliter ordinavimus: quod de bonis et hominibus quondam incliti patris nostri adversum ducem Bawarię et heredes eius numquam actionem habebunt.
Item, feoda quę interfectores regis Ph[ilippi] marchi[o]a Hyst[ri]ięb et palatinus comes de Witlingispahc ab Imperio tenuerunt sepedicto duci et heredibus suis concedimus et confirmamus.
Nemus quod vocatur Bazhart cum castro Nwenburc ad opus ducis omni iure conservaturi, sicut ipse dux nos instruere poterit et docere.
Ad cuius rei certam evidentiam et perpetuam in posterum firmitudinem fide data promisimus, et iurare fecimus in animam nostram comitem Adolfum de Schowinburc, Cunradum de Dicka, Bernhardum de Hurstimar nobiles viros et fidelem nostrum Gunzilinum dapiferum, quod cuncta quę premissa sunt inviolabiliter curabimus observare, et cum sigillo nostro sigilla principum quę postulavit huic cartę iussimus adhiberi.
Datum apud Vrankinfort, anno Dominicę incarnationis millesimo CoCo VIII, indictione XIIa, XVII kalendas decembris.
(SP D) (SP D) (SP) (SP) (SP D) (SP D) (SP) (SP D) (SP D) (SP) (SP)
a) sic marchi A. b) sic Hystię A, nisi Hystire seu Hystieę, sicut leg. Rzihacek et Spreitzer et Hystrieę em.
The official charter issued to Duke Ludwig of Bavaria following the imperial Diet of Frankfurt solemnly bestows upon the recipient not only the Duchy of Bavaria as a hereditary title, but also the fiefs that had been stripped from the murderers of King Philip, namely Bavarian Count Palatine Otto VIII of Wittelsbach (Duke Ludwig's cousin) and Henry IV of Andechs, the margrave of Istria.
The margraviate of Istria thus passed on to the incumbent duke of Bavaria, but Ludwig would not hold the region for long. A few months later, on the imperial Diet of Augsburg held in January of 1209, Wolfger, the patriarch of Aquileia, protested this investiture and asked the Margraviate of Istria for his Church based on an old donation charter of King Henry IV issued in 1077 (and revoked in 1079; see it edited here). King Otto IV complied and granted the Margraviate of Istria to Patriarch Wolfger and the Church of Aquileia, thus initiating a long era of Aquileian lordship over Istria.
The entire story arc, beginning with the murder of King Philip, is summarized in the editor's comments here.