Is the Civita shoulder bag allowed in museums in Rome?
There is no uniform, single answer. It depends on the property. Each has their own rules and varies some from day to day or how the guard might feel. For example -- the Borghese gallery prohibits ALL bags.
Based on my experience in February 2017, the Borghese now allows "small" bags. If it were a backpack, they'd make you check it, but that size for an over-the-shoulder bag is probably okay, maybe borderline. I saw women with handbags about that size in the galleries.
I went to see the description of the "Civita" shoulder bag: Civita
And, after watching the video, now I need to vent about something: Is it really that difficult to get the correct pronunciation for a non-English word if you are running a European website? The website (and the video) says that Civita is pronounced (chee-VEE-tah)
Nope. Listen to this real Italian to see that it is pronounced with the emphasis on either the first or third syllable, but definitely not the second. In other words, TSHEE-vee-tah or tshee-vee-TAH, but no way does it rhyme with Velveeta.
Sigh.