Athelney, small eminence, formerly an island, rising above the drained marshes around the confluence of the Rivers Tone and Parrett in the administrative and historic county of Somerset, England. In 878 King Alfred sought refuge from the Danes in the marshes and constructed a stronghold at Athelney, from where he broke out and won a decisive victory at Edington, near Chippenham. He later founded a monastery on the island as a thank-offering for his victory. The Alfred Jewel, an ornament inscribed with Alfred’s name, was found at Athelney in 1693.