Reseaching early keyboard layouts, Wiki states that early keyboards, to facilitate Gregorian chant, had eight white keys per octave, leaving just four 'black keys' - which may well have been white, as the colours were reversed - another story!
It's well known that along with A, B, C, D. E, F and G, B♭ was incorporated in pieces. Hence B♮ was called (and still is) H in German.
Question is - why would B♭ and B♮ be arranged in such a way that the lower pitched B♭ was on the right of the higher pitched B♮. Logically, that doesn't make sense.