Soapwort plant, mixed and agitated with water, gave early civilization its first cleaning agents before the soap was made.
According to Roman legend, natural soap was first discovered and takes it's name from a mount called 'Sapo' where animals were sacrificed. Rain used to wash the fat from sacrificed animals along with wood ashes into the Tiber River, where the women who were washing clothes in it found the mixture made their wash easier. But there is no such place and no evidence for the apocryphal story.
The first recorded evidence of soap making are Babylonian clay cylinders dating from 2800 B.C. Inscriptions on the cylinders are the earliest known written soap recipe and they describe a process by which fats could be combined with wood ash and water to create a substance capable of cleaning. The product thus produced was not necessarily used to wash the body; it might have been used to clean textile fibers such as wool and cotton in preparation for weaving into cloth.
The Ebers papyrus (Egypt, 1550 BC) refers to medicinal use of soap. These texts suggest that ancient Egyptians combined both animal and plant oils with alkaline salts to create a substance used for threatening sores, skin aliments as well as washing.
The Gauls and the Romans combined goat's tallow and the ashes of the beech tree to produce both hard and soft soap products. A soap factory complete with finished bars was discovered in the ruins of Pompeii, one of the cities destroyed by the volcanic eruption of Mt. Vesuvius in 79 A.D. While the Romans are well known for their public baths, generally soap was not used for personal hygiene and bathing. During the early century of the Common Era soap was used as treatment for skin disease. The importance of soap for personal washing was recognized during the later centuries of the Roman era.
The Celts used animal fats and plant ashes to create their soap, and they named the product saipo, from which the word soap is derived.
As for the Arabs, they produced the soap from vegetable oil as olive oil or some aromatic oils such as thyme oil. They made perfumed and colored soaps, some of them were liquid and others were hard.