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Definition of Ethelred the Unready
1. Noun. King of the English who succeeded to the throne after his half-brother Edward the Martyr was murdered; he struggled unsuccessfully against the invading Danes (969-1016). 
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1. Noun. King of the English who succeeded to the throne after his half-brother Edward the Martyr was murdered; he struggled unsuccessfully against the invading Danes (969-1016).