The researchers studied the strength of a type of masonry made with weak stone blocks and strong mortar in Matera, Italy. They tested the compressive strength of the stone blocks and mortar, and found that the strength of the masonry depends mainly on the stone blocks. By combining the strengths of the stone blocks and mortar, they could estimate the masonry's overall strength. The study showed that the strength of the stone blocks is crucial for the masonry's compressive behavior. The researchers also found that considering the strength variation of each component is important for predicting the masonry's overall strength accurately.