Complex sentence: The third of the three related religions, Christianity, although there has been a considerable history of aniconism in Christianity, has a long history of by an active tradition of making and venerating images of God and other religious figures.
Split into simpler sentences: The third of the three related religions, Christianity, varies greatly in the role of physical objects in religion. Although there has been a considerable history of aniconism in Christianity, there is an equally long history of active tradition of making and venerating images of God and other religious figures.