It isn’t every day I find an intriguing little snippet, but today was one of those days. This article tells the tale of the finding and opening of Charles I’s coffin- fascinating in itself, especially as it was found in vault considered to contain the coffins of Henry VIII and Jane Seymour, though the two coffins in question are not inscribed as such.
Charles I’s though does have an inscription and when opened the facial features relate to portraits of him, and the head was clearly severed, execution-style. So no reason to doubt it’s provenance.
But for me the part that really intrigues is the mention of a small coffin placed on top of Charles’ pall, covered in crimson velvet. A child clearly, but who?
The suggestion that it was a stillborn child of Queen Anne, (Charles I’s mother) while she was a Princess in Denmark seems, in my opinion, preposterous. 
1) She required to be a virgin when James VI married her and there has never been any suggestion that she wasn’t.
2) Why would the coffin of a child likely born many years earlier have been kept and re-buried along with Charles I?
3) (Most intriguing of all) Why would this be suggested?
If anyone can shed light on this for me, or point me in the direction of further information I’d be grateful – little snippets like this can be very useful, but they can also be VERY distracting…