Marsden found that the Kreutz sungrazers could be split into two groups, with slightly different orbital elements, implying that the family resulted from fragmentations at more than one perihelion. Tracing back the orbits of Ikeya–Seki and the Great Comet of 1882, Marsden found that at their previous perihelion passage, the difference between their orbital elements was of the same order of magnitude as the difference between the elements of the fragments of Ikeya–Seki after it broke up. This meant it was realistic to presume that they were two parts of the same comet which had broken up one orbit ago. By far the best candidate for the progenitor comet was that seen in 1106 (Great Comet of 1106): Ikeya–Seki's derived orbital period gave a previous perihelion almost exactly at the right time, and while the Great Comet of 1882's derived orbit implied a previous perihelion a few decades later, it would only require a small change in the orbital elements to bring it into agreement.