Final answer:
In Frankish politics, marriages were pivotal in forming alliances and shaping power dynamics. Sibylla's marriage to a different man would have likely influenced successions and the balance of power in the Frankish kingdoms, similar to the effects observed during key transitions in the Merovingian and Carolingian dynasties.
Step-by-step explanation:
The shift in Frankish politics with the change of Sibylla's marital status would likely have significant repercussions. This is inferred from historical patterns shown in the Merovingian and Carolingian dynasties where marriages often played a crucial role in determining alliances and power dynamics. For instance, when Pepin became the first Carolingian king, he solidified his position through an alliance with the pope that was, in part, cemented through land grants. Moreover, Charlemagne's acquisition of power was influenced by his brother's death and the exclusion of his nephews from inheritance, which violated the traditional Frankish practice of partible inheritance, the division of lands among sons.
These incidences show the political importance of marriages and inheriting practices within Frankish society. Therefore, had Sibylla married a different man, the political landscape could have been altered significantly, potentially influencing successions, alliances, and conflicts for power among nobility and other monarchs.