What incident led to the separation of Blefuscu and Lilliput?

The separation of Blefuscu and Lilliput in "Gulliver's Travels" is primarily attributed to the controversy over how to properly break an egg, which stems from an edict issued by the Emperor of Lilliput. This law dictated that all subjects must break their eggs at the smaller end, a mandate that was met with resistance by some citizens of Blefuscu, who favored breaking their eggs at the larger end instead. This seemingly trivial difference escalated into a significant political and military conflict, ultimately leading to the split between the two nations. The incident highlights themes of absurdity and the ways in which trivial matters can lead to larger grievances, reflecting Swift’s commentary on political and religious conflicts in his society.