Here are all of my points my account is junk and here is the rest of my points

The technique was mural painting and he used either freshly laid or wet lined plaster. he also use water to merge it with the pigment and plaster creating a internal part of the wall

Domes and arches were seen as quite opulent, they're harder to make and they're also hard to understand as arches look as if they really shouldn't work. all of these factors contribute to them being used in churches along with costs to make such amazing designs