New research suggests that an English monk identified Halley's comet as a repeating visitor nearly seven centuries before Edmond Halley received credit for the discovery. Eilmer of Malmesbury reportedly recognized the comet seen in 1066 as the same object he had observed in 989.
According to accounts preserved by the 12th-century historian William of Malmesbury, the monk Eilmer, also known as Aethelmaer, understood the connection between the two appearances. Professor Simon Portegies Zwart of Leiden University and researcher Lewis reached this conclusion after re-examining the medieval texts. Their findings appear in the book Dorestad and Everything After. Ports, townscapes & travelers in Europe, 800-1100.
