Casiraghi is typical Lombard, Milanese and Brianza in particular, Casirago, almost unique, is probably a transcription error of the first, deriving from the toponym Casirago (CO) or Casirago (MI), a town from which Barbarossa moved to Milan to then destroy it. additions proposed by Carla Casiraghi In my research I found in a parish in the book of baptisms, in the same year, the two versions: the one related to my family (Casiraghi) and the Casirago version, in that case, however, the surname took the gender from sex of the unborn child, if it was a female it was Casiraga, Casirago if male. So I am not convinced that this is a mistake but rather a tradition. Casirago fraction now suppressed was part of the municipality of Montevecchia as well as Maresso the majority of whose inhabitants has this surname and that seems to be the original point. Moreover many Lombardy toponyms bear the suffix needle and many surnames the suffix needles. This seems to be related to agh or ager (field of) probably in this case Campo di Cesare (Caesar).
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