Born in
Rome, he was the son of Commendatore Camillo Luigi De Rossi and Marianna Marchesa Bruti, his wife, who had two sons, Giovanni and Michele Stefano. Two days after birth Giovanni was baptized in the parish church of
Santa Maria sopra Minerva. De Rossi showed an early interest in Christian antiquity. In 1838, in company with his parents, he visited
Tuscany, where the innumerable treasures of art completely absorbed his attention. In 1841, notwithstanding the protests of his anxious father, he visited, for the first time, under the guidance of the Jesuit
Giuseppe Marchi, one of the then much neglected catacombs. Despite having a significant age gap, De Rossi and Marchi continued their studies in archaeology together and became known as the "inseparable friends" as a result. He devised a strategy for the systematic and critical gathering of all Christian inscriptions in 1843. During the summers of 1844-50 he visited the territory of the ancient Hernici in Latium and also Naples; in this way the knowledge he attained of the period of the Roman Republic was not purely theoretical. Around that time, De Rossi made the acquaintance of
James Spencer Northcote, who had a keen interest in the archaeology of Christian Rome. Northcote and
William Brownlow, would later publish an English translation of De Rossi's
Roma Sotterranea. In 1853, the
Prussian Academy of Sciences approved financing for the
Corpus Inscriptionum Latinarum under the direction of
Theodor Mommsen,
Wilhelm Henzen, and de Rossi. De Rossi and Henzen were responsible for editing the Roman inscriptions, which make up the sixth volume of the
CIL. Although Mommsen was the project's overall coordinator, de Rossi contributed invaluable expertise in Christian archaeology and early Christian epigraphy to the collection. Despite being a devout Catholic, de Rossi was held in high regard by Mommsen and was his closest Italian collaborator. In 1873, he was elected as a member to the
American Philosophical Society. In 1877 he became foreign member of the
Royal Netherlands Academy of Arts and Sciences. In 1882, he was elected a member of the
American Antiquarian Society. In 1888 de Rossi discovered that the
Codex Amiatinus, the earliest surviving manuscript of the complete Bible in the
Latin Vulgate version, was related to the Bibles mentioned by
Bede. It was also established that the Codex Amiatinus was related to the
Greenleaf Bible fragment in the
British Library. For a thousand years the Codex Amiatinus was believed to be Italian in origin. It was only at that time that de Rossi discovered that the original inscription was that of
Ceolfrith of the English. Giovanni Battista de Rossi died at
Castel Gandolfo on 20 September 1894. == Major works ==