Wiglaf of Mercia (d.839)
Bott estimated that Wistan was probably a small boy when his grandfather Wiglaf died in 839.  If "small boy" translates to age 9, this would place Wistan's birth at 830.
However, Wistan was killed 10 years after Wiglaf's death, in 849 as a full adult religious figure who had the retinue of a prince of the church. This would appear inappropriate for a 19 year old. To make him aged 29 at his death would require making him 19 when he was a "small boy," which also doesn't fit. So as a compromise, make him aged 14 in 839, when Wiglaf died, thus born in 825, and this would make him aged 24 in 849 when he was a notable riligious figure.
Using the 25 year rule, this would place the birth of Wistan's father Wimund at 800, and the birth of Wistan's grandfather Wiglaf at 775.
Berhtwulf, a younger brother who succeeded Wiglaf as King of Mercia in 839.
Wiglaf was one of the three kings, reigning in rapid succession (the others being Beornwulf and Ludeca who succeeded Ceolful I, the last king of the Mercian line, who was deposed in 823. 
Prior to assuming the throne of Mercia, Wiglaf had been an earldorman of minor importance. 
Wiglaf was Duke of the Wiccii until he ascended the throne in 827.  In 829 Egbert of Wessex became immediate ruler of Mercia and overlord in name of Northumbria. Egbert's power declined however from 830-839. 
Wiglaf seized an opportunity and once more became King of Mercia in 831, rapidly restoring Mercian ascendancy over a wide area.
In 836 Wiglaf held a great assembly on Croft Hill, attended by the Archbishop of Canterbury and eleven bishops of the Southern Province.
Wiglaf died in 839. His son Wimund predeceased him. 
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