Shakespearean - Shakespearian - Shaksperean - Shaksperian

The adjective meaning 'to do with William Shakespeare' has several different forms.

• The latest edition of Fowler's MEU says, s.v. Shakespeare: "Now universally spelled thus ... The corresponding adj[ective] (and noun) may be written as Shakespearian (thus in the house style of OUP) or Shakespearean (in The Times)." These are quoted as authorities, so whether to use Shakespearian or Shakespearean is a free stylistic choice.

That article points out

• Shakespere "was the more usual form" in the early decades of the twentieth century "and was recommended by the OED (1913 [i.e. during the compilation of its first edition] and by Fowler (1926)" - the first edition, again. OED now uses Shakespearian.
  • Fowler's original (1926) article reads: "Shakspere, Shakespear(e), -erian, -earian, -ean, &c. The forms preferred by the OED are Shakspere, Shaksperian. It is a matter on which unanimity is desirable, & on which, in view of the conflicting arguments, it will never be reached unless an authoritative decision is accepted as such. Shakspere, Shaksperian, [sic] are therefore recommended."
  • By the second edition, (1956), the editor, Sir Ernest Gowers had amended this to ""Shakspere, Shakespear(e), -erian, -earian, -ean, &c. The forms preferred by the OED are Shakspere, Shaksperian. It is a matter on which unanimity is desirable, and it is unfortunate that the OED's verdict has not been accepted as authoritative. But the preference today is undoubtedly for Shakespeare. It is no use trying to withstand a strong popular current in such a matter; even the SOED [SOD] has had to conform. Shakespeare, Shakespearian are therefore recommended."
    • Shakespeare himself, writing in a time when there was no uniformity or conformity of spelling in English, signs his own name in different forms. One difficulty is that he signed in an abbreviated from, without using abbreviations consistently. On 11th My 1612, he signed a statement of his evidence in a lawsuit as "Willm Shakp"On March 10th 1613, it was "William ShakspÄ“r", where the '-Ä“-' indicates a shortening. This was his signature to the conveyance of a house; the next day, he signed a mortgage-deed to the same property as "W^m ShakspÄ“", where the 'W^m' is a conventional abbreviation for his forename.