Describe an important old thing that your family has kept for a long time

The object I'd choose is my grandfather's wooden writing box, which has been in the family for something like sixty years. It's not valuable in the slightest — plain dark wood, a brass catch that no longer closes properly, and a lid that has warped with the humidity. He used it when he worked as a village teacher, and it still smells faintly of ink. What's inside matters more than the box. There are letters my grandmother wrote to him while he was away, a few photographs with the corners gone soft, and his fountain pen, which hasn't written a word in decades. My mother keeps it on top of a cupboard and brings it down maybe once a year, usually around the death anniversary, and we go through it together. I find it strange and rather moving that an object this ordinary is the thing holding the family's memory. Nobody would look twice at it in a market. But it's the only physical trace we have of a man I never met, and I assume that one day it will be handed to me and I'll be the one deciding where to keep it.