The Constitutional Convention signed off on the term in 1787.
The states finally collectively adopted the proposed Constitution in 1788.
So evidence dated within or near to that time frame is all fair game.
Before, also probative.
> So evidence dated within or near to that time frame is all fair game.
Not after (as in near but after), if one wants to be uber strict. In cases such as this one (when there is a relatively change of nationality, involving changes of jurisdiction) it may be prudent to be (uber) cautious.