Ælfthryth of Wessex (died June 7, 929), also known as Elftrudis, was the last child of Alfred the Great, the Saxon King of England and his wife Ealhswith. She had four or five siblings, including King Edward the Elder and Ethelfleda.
Ælfthryth married Baldwin II (died 918), Count of Flanders.
They had the following issue:
Ælfthryth was the subject of the award-winning young adult novel Journey For a Princess by Margaret Leighton (1960: Farrar, Straus and Cudahy, New York, NY). In this book, she is called Elstrid.