Piscinas were introduced around 850 A.D. by Pope Leo, as a place to wash the vessels before and after Mass. They are usually situated in a niche at the side of the altar.
The Piscina in Slaidburn Church is made from red sandstone. It was originally painted red, green and gold. It has the interior shape representing Mary Magdalen, and has the Templar Rose in the bowl.
The Long Preston piscina is made from sand coloured sandstone. It was painted red, Iris blue and green. The design of the stone evokes Mary Magdalen, but the Iris blue represents Mary the mother of Jesus. Adoption of the Arum Lily came later.
Red represents blood and life. Green is the colour of illumination, initiation, nature and resurrection. Blue is for the sky and the Iris of the Virgin Mary. Gold invokes the divine brilliance of the sun and resurrection.