"The wife of Ine bore the name of Æthelburh. She was herself of the royal house, and her brother Æthelheard, who succeeded Ine in the kingdom, is spoken of as a kinsman of his predecessor." Proceedings of the Somersetshire Archaeological and Natural History Society18, pt 2, 15, [1]
books.google.com
The tradition is reflected in, and may stem from, a charter in Glastonbury, now considered spurious, in which he is identified as the queen's brother. However, even as a forgery, it has sometimes been valued as at least "some evidence, when not contradicted by anything better", to quote Edward A. Freeman (1872), "King Ine", Proceedings of the Somersetshire Archaeological and Natural History Society18, pt 2, 1–59, fn p. 15
cam.ac.uk
esawyer.lib.cam.ac.uk
Queen Frithugyth is identified in a charter of Æthelheard, king of Wessex, dated 729 indicating that they were at that time married, Charter S253 [3][non-primary source needed]
mcllibrary.org
The Anglo-Saxon Chronicle Part 1: A.D. 1 - 748 Online Medieval and Classical Library Release #17, [2] "A.D. 740. This year died King Ethelhard; and Cuthred, his relative, succeeded to the West-Saxon kingdom"[non-primary source needed]
