in a two-part article in Dulcimer Player News, (Winter 2001 & Spring 2001),
argues that a dulcimer, as we know it, was not technically possible until after
the mid 1300s when ways to make stronger cheaper wire was finally developed. Before
that, the wire was not strong enough to sustain the tension.
He has other arguments that discount earlier mentions of "dulcimer"
as more or less a translater's choice of words for some unknown instrument. He
also points out the total lack of any description of dulcimer, playing construction.