Depends on who you ask, it's sometimes used to refer to as late as the 1400's.

It wasn't a straight jump from Columbus or the Iberian unification, the Enlightenment and the late Middle Ages overlap a lot. I'd say from 1200's things began to 'instituonalize', from first proto-parliaments, to Iberian Fueros, to different merchants and thinkerers eroding the Ancient Regime a little by supporting capable people with the money of rich people (Maecenas? in Latin).