Isabel Zendal
Rectress of the Corunna Foundling Home and the only woman on the Royal Philanthropic Vaccine Expedition (1803-1813), responsible for the care of the foundling boys whose arms carried the smallpox vaccine across the Atlantic and the Pacific. Her surname appears in the documents in several variants (Zendala, Sendales, Cendales); she remained in Mexico, where her final whereabouts are unrecorded.
Why this wins its question: Zendal is mostly told through commemorations, with unstable facts and an invented biography circulating online. This object is bound to the archival scholarship (Mark and Rigau-Pérez, read in full), including the documented name variants and the honest gaps — what is not known is stated as not known.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Isabel Zendal (recorded in expedition documents as Isabel Zendala y Gómez, among other variants) was rectress of the Corunna Foundling Home and the only woman to participate in the Royal Philanthropic Vaccine Expedition.
Her assigned duty was the care of the twenty-two nonimmune foundling boys, aged three to nine, who transported the live vaccine by serial arm-to-arm inoculation on the ocean crossing, and of the many children who succeeded them in the chain.
She continued with the Balmis group to New Spain and the Philippines and settled in Mexico; the sources last place her in Puebla, and no record of her death has been found.