A key factor in our ability to carry out historical linguistics work on signed languages has been our creation of a database containing historical corpora of the early stages of ASL. In turn, this allows us trace the history of morphological persistence and change among co-dependent forms sharing a common grammatical function. The observation of these processes in sign languages over time provides evidence for cross-modal validity of the grammaticalization model described in Givon (1979) and reproduced in Brinton & Traugott 2005 as follows: Discourse > syntax > morphology > morphophonemics > zero. The opaque forms we find as relics, left over from obsolete paradigms in ASL, illustrate the “zero” endpoint of grammaticalization. Such forms do not appear in young sign languages. As in spoken languages, grammaticalization proceeds in a unidirectional fashion. In fact, the historical linguistic research show similarities across sign and spoken languages and are suggestive of universal linguistic and cognitive patterns.