What kind of key for this old door (mortise lock)? - Home Improvement Stack Exchange

I am helping someone with a lost key for her bedroom (interior) door; the door hardware is probably about 100 years old. There is clearly a lock and a keyhole -- see photos. What sort of key would

doors - Options for replacing mortise lock with keyless lock

Any door hardware gurus? Wondering if my front door hardware can

repair - Key stuck in door lock - Home Improvement Stack Exchange

Right Swing, Fancy Vintage Lock Set, Mortise Lock With Glass Knobs

Newliplace Mortise Lock Set for Interior Door, Vintage Door Knobs with Lock and Skeleton Key, Antique Door Knobs Oil Rubbed Bronze Finish

How to tell what brand a door lock is? - Home Improvement Stack

lock - Stuck padlock without key - its attachements to the door

How do I find a replacement door lock for this? - Home Improvement

Toptotoo Mortise Lock Set for Interior Door, Vintage Antique Door

Toptotoo Mortise Lock Set for Interior Door, Vintage Antique Door Knobs with Lock and Skeleton Key, Old Door Knob Replacement Fits 1-3/8 in 1-3/4 in, Brushed Satin Nickel Finish