You maybe stayed in that house in Rome but didn’t live in it. I grew up in a 100+ year old stone and mortar house with almost 1.5m thick walls and relatively good window insulation. The problem is the thermal capacity of those walls. When they heat up during a hot summer spell it’s like living in an oven. You cannot sleep most nights during the summer. Something similar happens in the winter too, if you go on a vacation. The house gets so cold you need couple of days to warm it up again. When my parents installed AC it was heaven during summer.