The pavement belongs to a type of inlaid stone decoration known as Cosmati work, after one of the families of craftsmen who specialized in it and the technique is called opus sectile, 'cut work'. This differs from ancient Roman and earlier medieval mosaic work which consists of square stones of equal size.

The floor of Westminster Abbey features one of the most significant medieval treasures in the world: the Cosmati Pavement. Located in front of the High Altar, this intricate mosaic floor was commissioned by King Henry III and completed in 1268. It is made of thousands of precisely cut pieces of colored stone, including purple and green porphyry, onyx, and "Forest Glass," set in a bed of dark Purbeck marble. The patterns form a complex "quincunx" design (a central circle surrounded by four others) that symbolically represents the universe and the end of the world. Beyond this mosaic, the Abbey floor is also "home" to hundreds of burials and memorials; most notably, the Grave of the Unknown Warrior is located near the West Door, surrounded by poppies and never stepped upon. For 2026 visitors, seeing the Cosmati Pavement uncovered is a rare treat, as it is often protected by carpets to preserve the fragile, 750-year-old stonework from the millions of feet that pass over it.