Juan Bautista Chapa was born Giovanni Bautista Schiapapria in 1627 in Albisola, Italy, and is now recognized as the "anonymous historian" of Nuevo León, Mexico, where he arrived in the mid-seventeenth century and served Governor Alonso De León and other governors as their secretary for over four decades. Chapa knew these officials well, traveled through the province extensively, and wrote his observations of developments in that far northern region in Historia del Nuevo Reino de León de 1650 a 1690. The chapters of this work that treat Texas analyze the motives, frustrations, and strategies of Spanish expansion to the rim of the empire and constitute one of the most important primary sources for history in early Spanish Texas. The expeditions Chapa participated in include De León's first expedition in search of René Robert Cavelier, Sieur de La Salle's Texas colony, from Cadereyta to the mouth of the Rio Grande, and his second, which is generally supposed to have reached Baffin Bay. Chapa also joined De León on his 1689 expeditions that found the ruins of La Salle's Fort St. Louis.
His observations are particularly important because of the political impartiality he maintained by writing the book secretly and anonymously. He was a well-educated man who knew Italian (including the Genoese dialect), Spanish, Latin, and Tuscan. He left behind a perceptive and well-crafted historical work. The authorship of the Historia remained a mystery until 1961, when the edition published by the Biblioteca de Nuevo León revealed his identify.
Chapa lived out his life in Nuevo León and married Beatriz Olivares de Treviño, daughter of one of Monterrey's elite families. They had four sons and two daughters. Chapa died in Nuevo León in 1695 and is recognized as the ancestor of the very numerous Chapa families of northeastern Mexico and South Texas. Norman P. Brown has researched the Chapa descendants in Chapa: The First Four Generations, which covers the period from 1651 to 1800. Juan Bautista Chapa's own ancestors have been documented by Amancio J. Chapa, Jr., of La Joya, Texas.