I don’t believe the WHOLE myth, and like I said my judgment is based in “lack of inherent implausibility.” If Saramago was simply reconciling two divergent “traditions” that’s fine with me.
There’s a (possibly apocryphal) story that Shakespeare took to his final deathbed after a night of heavy drinking with Ben Jonson at an inn in Stratford. When I was in Stratford, only a few of the residents were familiar with the story, and NOBODY knew which inn it was supposed to have been. But there are a couple of inns still standing which date back to at least 1623, so I unilaterally decided that the one I was in (the Thatched Roof Inn) was where Will’s Last Carouse took place, and the table where I was sitting (by the window) was where he and Ben sat. I went so far as to suggest that, so long as no OTHER tavern in town was making the claim, they should put up a little placque and promote themselves as such (Stratford is basically an “Industry Town” these days anyway, the industry being Shakespeare).