Antique box from Russia with engraved bone plates, first half of the 19th century

Antique Russian box covered with bone plates featuring beautiful engravings. This box is likely to date from the first half of the 19th century, with an old letter in Cyrillic script attached to the bottom indicating its age and origin. Unfortunately, it is almost inevitable that this delicate material will not survive 150 to 200 years unscathed. The mere fact that the box has survived the considerable number of major wars during this period is remarkable in itself.
Condition: The box has some damage, some of which has been repaired (see photos). However, its age is evident, but this patina is part of the box's history. Structurally, the box is in good condition, it is stable, the hinges work perfectly and all the bone plates are firmly attached to the substructure. The key is not original, but works with a little skill and caution.
Dimensions: width 22 cm, depth 15 cm, height 10 cm