On your left when you come in is this pillar with a large black stone sitting on it... legend has it that Satan threw this stone down at St. Dominic while he was praying here in Santa Sabina's, making some big cracks in one of the stone tiles in the choir floor. (History 101 for today - the stone itself is one of the old Roman "weight" stones that was used to measure amounts of product in big scales to gauge the price value.)