The fact that there's no mention of Wonder 13 being in an Anglo-Saxon area might provide dating evidence for this part of the list. Other areas that contain wonders and which are under Saxon control are listed as such. The area of this wonder was under Saxon control by the time the Historia is estimated to have come together around 830CE (for example, it seems likely that Hereford is the Herefinna listed as part of Saxon Mercia in the Tribal Hidage [See Other Works]). The absence of this detail is therefore strange.

This border area was subject to a variety of fluctuations between Saxon and British ownership*, such that it is hard to give a definitive last-date for British rule, but the area was broadly within the Saxon kingdom of Mercia by a reasonably early stage. The following are some of the key events up to 850 (unless otherwise stated these are from the Anglo-Saxon Chronicles: See Other Works)...

• 522: Caradoc probably king of Ergyng after this time (Book of Llan Dâv: See Other Works)*
• 577: Gloucester, Cirencester, and Bath fall to the Saxons
• 584: Fretherne (Info) taken by Saxons, but they then retreat back from here.
• 593: Death of Cryda, originator of Mercia, who may have given his name to Credenhill near Hereford*, possibly suggesting an early Saxon presence.
• 607: Saxons take Chester, infamously slaughtering a large body of monks who had come to pray for the Welsh in the battle.
• 633: Alliance between Mercian King Penda and the British King Cadwallon, who attack the Northumberland Saxons.
• 661: Saxon's fight the British at Pontesbury.
• 676: 1st Saxon Bishop of Hereford.*
• 760: Battle of Henffordd [Hereford?].*
• 796: Offa, king of the Mercians, dies*. His dyke (Info) runs down the borderland. While it is moot as to whether dykes in Herefordshire are part of this, the general trend of the dyke would be to run through Garway if its natural continuation is the Wye valley.
• 800: Mercian royal residence near Hereford.*
• 823** & 853*: Mercians take Powys
• 828: King Egbert of the West Saxons subdues North Wales.
• 835: West British join with Danish boatmen to attack Egbert at Hengeston(in the South West?)

The fact that Bath (Wonder 3) and Droitwich (Wonder 4) are listed in Saxon territory, but this is not, might suggest a date between 577 and 676, though, of course, the absence could be for a number of less significant reasons. The Hwiccae, the tribe under which Bath and Droitwich are given, may have been founded by Penda (c.620: Info), however, Bede uses the tribe when referring to a meeting in ~603, making it hard to give a more concrete earliest date other than 577.