A paleta, or paleta helada, is pretty much like a popsicle (as they’re known in the U.S.) or an ice lolly (as they’re known in Britain). The difference is that a traditional Mexican paleta is made with real fresh fruit juice, and sometimes carries chunks of real fruit in it.
While the history of ice cream has been well-documented — it’s thought to have originated in China, and was eventually brought to Europe by Marco Polo — the history of the paleta isn’t quite so detailed.
An old Mexican legend says that the Aztec emperors had servants who would bring ice from the Popocatépetl volcano, outside Mexico City. The emperors would eat this ice, mixed with fruits. This sounds exotic but isn’t backed up by written historical sources. What we do know is that during the Viceregal times, the historical name for the period of the Spanish conquest, the Spanish crown regulated and monopolized the ice market. People paid high taxes to have access to it.
After Mexico gained its independence from Spain in 1810, this taxation was lifted and the ice market opened up. More people had access to ice. Therefore, more people experimented with it.