It's what in my family might have been referred to as a kist - we had one when I was a child, though without legs. I suspect the date might be genuine, though obviously I can't prove it. However, it does look pretty old, and competently made (jointed, fixed with dowels/pegs), though not of the very finest quality - rustic might be a good description. The hinges are obviously modern, and you can see the holes where much larger hinges had been fixed, but the reinforcements holding the lid together look like a much older repair.
I suspect an item like this could have been used for storing almost anything (or everything) a family owned. Linen, clothes, family Bible, miscellaneous odds and ends, etc, etc. And it could double up as somewhere to sit.
I wonder if it could have been a wedding present, and CL was the bride, this being a key item for the new home? But something like this could have changed hands or location many times in 300 years, so finding its ultimate origin may be challenging.
