A low, leather Box.
The box has been relined in marble paper and was probably fitted to take cutlery when first made. The interior is now plain and it will fit documents upto 14 1/4 inches (36cm) by 10 1/2 inches (27cm) in size. When open, it has a ribbon to hold the top up and when closed a pair of brass twist catches to lock it. It has a small swan neck handle to the top with a plate which is engraved with the entwined initials which may be an A and a S.
It's possibly French and late 19th Century.