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Edmond Halley connected separate historical appearances of a comet by comparing their calculated orbits. In his 1705 synopsis he argued that the appearances of 1531, 1607 and 1682 belonged to the same returning body.

The important step was a testable prediction: the comet should return, with its timing affected by gravitational perturbations from the planets. Its later return in 1758 supported the interpretation. The achievement applied orbital dynamics to historical observations rather than treating each bright apparition as an unrelated event.^[ref]