Livre d'Or

Ooh, that makes sense with the leap months and the idea that 33 is one and a bit times 19; I shouldn't have expected a whole number multiple. And the original tweet did say roughly every 33 years, I think it might well be 32 or 34 sometimes depending exactly where we put our leap months. (And yes, I was just thinking, the same new moon, not worrying about the one or two day offset between observed and calculated new moons.) Thank you for being helpful and explaining!