According to Owlcation, King Charles I wanted to implement tax reform by increasing taxes on Jacks, or half-pints, but Parliament refused to do so. Undeterred, the king decided instead to simply reduce the volume a Jack would hold, by lowering the imperial measure of the half-pint line, which was indicated by a crown symbol. Thus, Jack "lost his crown" and a reduced volume on the Gill soon followed, or "came tumbling after." And with the volume on Jacks and Gills reduced, King Charles I got his tax increase without technically raising the prices on the beverages.

However, while this seems to be the most likely theory as to the origins of this popular nursery rhyme, it is far from the only one. Another common interpretation is the idea that the lyrics are really about the beheadings of France's Louis XVI and his wife, Marie Antoinette, although the timeline of these events and the publication of "Jack and Jill" do not line up. The French Revolution was about 30 years after the publication of the nursery rhyme, thus making this theory unlikely, per Mental Floss.

ncG1vNJzZmivp6x7qL7Up56eZpOkunCAmGtvcm9fqbWmecOaqaRln6e2qLXNrGSonl2ptaZ5yZqapGWRo7Futsilo2ampafApr7YZqmhsZ2afA%3D%3D