Saint Mary (the Blessed Virgin) with the Christ Child, and Saint Roch, as Protectors Against Earthquakes (1800-1899) - Public Domain Catholic Drawing

The image is an engraving from the 19th century, as indicated by the date range you’ve mentioned (1800-1899). The engraving features the Virgin Mary, known as the Blessed Virgin, holding the Christ Child, with two saintly figures, one of which is identified as Saint Roch, recognizable by the pilgrim's staff and the sore on his leg, indicating his affliction during the plague, which he is traditionally known to have survived. Saint Roch is commonly invoked as a protector against plagues and, by extension, other calamities such as earthquakes.

The other saint remains unidentified but is likely known to be associated with protection against earthquakes or is a patron saint of the local region where the engraving was made or found. The inscription "B.V. DEL CANOSSA IN MANTOVA DETTA DEL TERRAMOTO" refers to the Blessed Virgin of Canossa in Mantua, known for protection against earthquakes ("terramoto" being the Italian word for earthquake). This suggests a specific local veneration, presumably in or connected with the Chiesa della Madonna del Terremoto, Mantova, built in thanks for protection by the Virgin Mary from the earthquake of 1693.

The technique used is line engraving, a method where the artist creates the image by incising lines directly onto a metal plate, usually made of copper. This plate is then inked, wiped clean (leaving ink only in the incised lines), and pressed onto paper to create the print. Engravings of this type were often used for religious iconography, making art more accessible to the masses by reproducing images that could be distributed more widely than unique paintings or sculptures.

The monochromatic palette is characteristic of engraving, focusing on form, light, and shadow rather than color. The clarity of the line work suggests a combination of both the reverence for classical art forms and the technical precision that was valued during the period. The artwork is a reflection of the 19th-century aesthetic values and serves a devotional purpose, as indicated by its subject matter and the protective role it suggests for the figures depicted.