The practice of making time capsules may be as old as time itself.
Cave paintings are perhaps the first time capsules.
They depicted who we were, what mammoths we killed, and what mammoths killed us. The oral tradition, and storytelling are a kind of time capsule, they preserve the collective memory over generations. You owe me three cows. However, these are all gestures of the moment, a record for the present. The cavemen were probably not thinking about posterity's interest in their society, nor were the prehistoric taxmen.