From reading Gaudi’s baptismal certificate dated June 26, 1852, one day after his birth, which is preserved in the Archdiocesan Historical Archive of Tarragona, we can see that the future architect was called “Anton Placito Guillem” (without accents, as in the entire document).

Gaudí’s baptismal certificate, preserved in the Archdiocesan Historical Archive of Tarragona, and detail of the inscription of the name “Anton Placito Guillem”

The baptismal certificate shows clearly Gaudí’s middle name was “Placito”, as well as in the same certificate, Gaudí’s godfather, to whom he surely owes his second name, is mentioned as Placito Gaudi Torne. The author of the well-known illustration of Gaudí’s family tree, Josep M. Armengol Viver, had already published the correct transcription of the document in 1936, that is, mentioning the baptismal names “Anton Plàcito Guillem”, with the accent. 

Priory Church of Sant Pere in Reus, where Gaudí was baptized on June 26, 1852. The font in which he received baptism no longer exists as it was destroyed during the Spanish Civil War. Photos: Wikimedia commons

Article by J. M. Armengol Viver published in El Matí on june 21, 1936 commemorating ten years since Gaudí’s death with the study of the architect’s genealogy and the exact transcription of his baptismal names: “Anton Plàcito Guillem”