Theobald von Oer was born in Westphalia in northwestern Germany and began his primary art training at the Dresden Academy at age 19. He was an extremely talented student, and he went on to finish his studies at the academy in Düsseldorf. A member of a baronial family whose title he would later inherit, von Oer was the victim of a childhood illness that left him with little hearing and some difficulty with speech. His brother Maximilian was a writer of Germanic chivalric poems.

The von Oer brothers explored literary Romanticism in different ways. Theobald became a well-known painter of scenes from German literature and history and painted many scenes of court ceremonies. The Allegory of Mining is unusual in his oeuvre and uniquely suited to its future home in California, a state founded on the industry. The poem at center and on banners carried by the angels at upper right and left deals with the nobility of mining. Within the earth, a crystal-crowned allegorical figure presides over a world filled with pleasures and dangers, which are represented by the discovery of precious stones and the man overcome by fumes. On the surface, figures dowse for minerals and give thanks for their safe journey underground, while in the background mining families take part in a rustic celebration near the furnace where ores are refined.