That shrine in Ascalon was established at the end of the fifth century AH; it was not ancient. Before it, there had been no site there, or anything similar, associated with al-Husayn, nor any inscribed stone or anything else that might be cited as evidence of such an association. It is thus clear that attributing such a place to al-Husayn is a claim made without any knowledge whatsoever. Whoever makes this claim has nothing that could serve as a basis for it—not a sound report, nor even a weak one. Indeed, this is no different from someone coming to some graves in a Muslim city and claiming that one of them contains al-Husayn’s head, or that a particular grave belongs to one of the prophets, or making similar claims of the kind often advanced by people of falsehood and misguidance. It is well known, and Muslims agree, that no such claim has been transmitted.
What such people generally rely on is a claim to have had a dream, or to have found at the grave some sign indicating the righteousness of its occupant: a pleasant fragrance, an imagined occurrence beyond the ordinary, or something similar. Alternatively, they rely on an account that someone used to venerate that grave.
As for dreams, many—indeed, most—are fabricated. In our own time, we have known people in Egypt, Syria, and Iraq who claim to have had dreams concerning certain places, to the effect that a particular place is a prophet’s grave, or contains a trace of a prophet, or something similar, yet the claimant is lying.