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I happened upon a scrap of hand-written Latin that refers to the question in the title (above). It appears to quote Janus Dousa (1545 - 1604) as its source, and names Theodore V (son of Floris / Florence I) as the first title holder for the County of Holland in 1075. This seems to contradict the County of Holland article, which currently has Floris (Florence) II in 1101 as the first title holder.