Royal Copenhagen Porcelain Marking with Production Date '1858'

The image displays the base or underside of a white ceramic or porcelain item, featuring distinct manufacturing marks. Central to the composition are the iconic three blue wavy lines, a well-known motif of Royal Copenhagen porcelain. Above these waves, a faint circular stamp is partially visible, likely the Royal Copenhagen crown mark, though it is somewhat obscured and discolored with light brown or ochre-toned staining. To the left of the blue waves, the number '1858' is clearly visible, hand-painted in black. This numerical marking strongly suggests a production date, indicating the piece was manufactured in the year 1858, placing it within the 19th century. To the right of the waves, there appear to be additional hand-painted numbers or initials, '1C.B.' though this portion is slightly less clear. The surface of the porcelain is glossy white, but exhibits significant signs of age and handling, including dirt, grime, and potential residue in various shades of brown and grey, particularly around the manufacturer's mark. There is also a small, circular, dark hole, possibly a ventilation hole or a mounting point, located towards the upper left of the visible area. The clarity and precision of the hand-painted '1858' and the blue waves suggest good craftsmanship despite the age-related wear. The item appears to be an antique piece of Royal Copenhagen, highly collectible due to its age and the clear date marking.