Hamlet vocabulary

Here the poet has preserved the manners of the ancient Danes, with whom it was religion to swear upon their swords. I was once inclinable to this opinion, which is likewise well defended by Mr. Upton; but Mr. Garrick produced me a passage, I think, in Brantoms, from which it appeared, that it was common to swear upon the sword, that is, upon the cross which the old swords always had upon the hilt.