To enter the churches in Rome, Florence and Venice, you do not need to "dress up". Just don't wear sleeveless shirts and cover your knees. Some places were fussy. Outside the Vatican, there are vendors selling scarves that many women wrapped aroung them or bring your own. Some churches in Florence gave people paper smocks. To be on the safe side, wear shorts sleeved shirts and long pants or capris. I wore zipoff pants in Rome and Florence. After viewing a church, I just zipped the legs off and wore shorts the rest of the time. Good walking shoes are essential. A hat and sunscreen are necessary too.