Depends upon the quality of the coffin and the amount of moisture in the ground. How well-off was this person? Would they have been buried in what amounted to a top-of-the-line coffin in that time, or your standard, cheap wooden box? Is it a wet season or a dry season?
In a standard wooden box with a fair amount of moisture, I'd say a few weeks; in a nicer coffin, it could probably take several months.
Non-fleshy things will last longer, but their decomposition is going to be affected by the same factors. After a few months, you'd likely still be able to find bones, hair, clothes... certainly glass or metal items... probably wood items... maybe paper items, depending.
To give you an idea -- I was involved with a historical archaeology project at this time last year. Our artefacts went as far back as the 1920s or so. We found a lot of glass, of course. Any paper that would have been on the glass was long gone. There was a lot of metal, although it was VERY rusted, some of it to the point that it crumbled to nothing if you tried to move it. There were a few animal bones, but only very dense ones remaining. In some of the upper layers (say, around the 40s or 50s) we found a few tiny scraps of fabric. There was some wood, but it was soaked and fragile and fragmented.
Re: On Decomposition
In a standard wooden box with a fair amount of moisture, I'd say a few weeks; in a nicer coffin, it could probably take several months.
Non-fleshy things will last longer, but their decomposition is going to be affected by the same factors. After a few months, you'd likely still be able to find bones, hair, clothes... certainly glass or metal items... probably wood items... maybe paper items, depending.
To give you an idea -- I was involved with a historical archaeology project at this time last year. Our artefacts went as far back as the 1920s or so. We found a lot of glass, of course. Any paper that would have been on the glass was long gone. There was a lot of metal, although it was VERY rusted, some of it to the point that it crumbled to nothing if you tried to move it. There were a few animal bones, but only very dense ones remaining. In some of the upper layers (say, around the 40s or 50s) we found a few tiny scraps of fabric. There was some wood, but it was soaked and fragile and fragmented.