Odds and Ends
11 10, 3:05am
Basically all of that is just straight up incorrect - and the link you provided clearly says so.
If anything it seems most like Thanksgiving - while there's actually no connect to that genuinely American celebration:
"Because of this, St. Martin's Feast is much like the American Thanksgiving - a celebration of the earth's bounty."
Apparently someone have at some point also called this celebration "Old Halloween" or "Old Hallowmas Eve" - but I can't think why.
In Sweden it's definitely not associated with anything resembling Halloween at all - and the only mention of it besides the name I gave above is in reference to Holland.
Not even in the US this holiday is the same as Halloween - it's a separate celebration held mainly in parts of the German community.
Also there is nothing to support your assertions about any "pre-christian roots" at all - the entire celebration comes from the Catholic Saint Martin of Tours, so it's clearly Christian in origin.
Which leads to the question if you read up on this at all or just dreamt it? Truly bizarre claims to make...
Just go back and read your own source.