Giovanni Battista (Carlo) de Rossi (23 February 1822 – 20 September 1894) was an Italian archaeologist, famous even outside his field for rediscovering early Christian catacombs. Life and works 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. He studied philosophy the Collegio Romano from 1838 to 1840. He then studied jurisprudence from 1840 to 1844 at the Sapienza, where he was graduated with the degree of doctor utriusque juris ad honorem. 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. As soon as he had finished his studies De Rossi was appointed scriptor at the Vatican Library and bore this modest but honourable title, in which he took especial pride, all his life. Great credit is due him for his careful cataloguing of hundreds of Vatican manuscripts. The free use of the treasures of the Vatican Library and archives was a rich source of development for his intellectual powers, especially in the sense of breadth of interest. His official duties were not heavy, and he was able to carry on his private studies without hindrance. He applied the sciences of archaeology and epigraphy, and leveraged his thorough knowledge of the topography of Rome, not to mention the resources of the Vatican Library, where he was employed cataloguing manuscripts. These skills he brought to Early Christian sites and guided the development of a new field, Christian archaeology. He travelled widely, knew all the museum collections intimately and was