Italian here, and it was the same for me, the language feels very different by 1300.

Which is interesting cause 1200 italian[0] seems pretty readable by everyone who can read italian (and likely every other romance language), you have to go further back to have a shift.

[0] E.g. Saint Francis' Canticle of the Sun https://en.wikipedia.org/wiki/Canticle_of_the_Sun