The Scuole Grandi — or the Great Schools — were Venetian medieval charities which due to their wealth became important institutions
The constitution of the Republic of Venice never really existed. The Venetian nobility just made it up as they went.
The Venetian state was always an ad hoc construct, and institutions came and went at the convenience of the ruling elite.
The Republic of Venice changed continuously as conditions inside and outside of it changed, until it gradually found its final form in the 1300s and 1400s.
“Inquisitori alle Scuole Grandi” from the Lessico Veneto (1851) by Fabio Mutinelli, translated by René Seindal.