King Arthur is a variant of Arthur (Thinline) with stroke contrast. Designed by Roc Mitchell, it has alternates named Guinevere. [Mitchell] It was issued as part of Alphabet Innovations, vol. 4 in the early 1970s. Light and Out(line) styles followed in vol. 5. [1976 specimen] Alternatively, it was issued as part of vol. 2 in 1971. [Martin] Other sources give a 1974 date. [Oka] Carried by Castcraft as Knight with Knight Gawain (Light) and Knight Outline. [Castcraft 1978]
Mitchell showed a digital version of the Arthur series as Poetry. [2000 web archive] The new name was introduced in 1993. [Oka]