[dan_mctree]

Considering the Dutch connection. Thanksgiving may've just been a continuation of the Dutch dankdag/Thanksday, which is a small protestant celebration thanking God for the harvest. They do that every year, regardless of the circumstances, and it kind of sounds like they just continued that practice.

Harvest festivals in general were common throughout Europe and many immigrants would be familiar with them, so it's not very surprising that at least one version of it would survive.