Some physical abnormalities such as microencephaly result in stunted mental development, those who suffered from microcephaly such as Maximo and Bartola were easily exploited. The siblings each had underdeveloped skulls and brains and a diminutive stature and in the sideshow were referred to as pinheads.

The brother and sister were born to Burgos and Marina Espina in Decora, San Salvador where they caught the eye of a trader, Ramón Selva. Selva, a less than honorable man, convinced the parents to hand over the children so he could take them to the U. S. to “cure” them. Once he had custody of the pair, he sold them to an American named Morris who began exhibiting them as The Aztec Children. This was the first example of performers being promoted as members of an exotic race.

The children would dance and talk in gibberish and were dressed in Aztec inspired clothing decorated with sun symbols. But their fame was not limited to circus audiences alone, the scientific community found them intriguing as well. They were brought before the Boston Society of Natural History and the Ethnological Society in England. J Mason Warren, M. D. published a paper about them in the Journal of the American Medical Sciences.

Throughout their travels they met with the British Royal Family, Emperor Napoleon, Emperor of Russia and the Royal Families of Prussia, Bavaria, Holland, Hanover, Denmark and Australia. They were also the guests of President Fillmore.

On January 7, 1867 they married in London at the registrar’s office under the names Señor Máximo Váldez Núñez and Señora Bartola Velásquez, most likely as a promotional stunt. But few records exist beyond that date.