Before the advent of Islam, the Arabs did not form a coherent unit. At the beginning of seventh century Arabia is positioned around two empires that they face. To the west, Byzantium, Christian and heir of Rome ruled North Africa, Palestine, Syria, Anatolia, Greece and southern Italy. In the East, the Persian Sassanid Empire occupies an area that corresponds to the current Iraq and Iran and had as its official religion Zoroastrianism, but it also lived Christians, Jews and Manichaean. The western Saudi stood Abyssinia, who professed Christianity Coptic.
The basis of this society was the tribe that brought together descendants of one ancestor. A tribe consisted of several clans and extended families that grouped under the authority of a man. Some tribes were sedentary and others were nomads (Bedouins). The tribes lived in constant warfare.
From the religious point of view, Arabia was the land of polytheism, but also lived it monotheistic communities. Jewish tribes, perhaps arrivals to the Arabian Peninsula after the destruction of the Second Temple in 70, formed communities that inhabited the local Fardak and Yathrib, a name pre-Islamic city of Medina. Some northern tribes of Arabia had converted to Christianity Monophysite or Nestorian Christianity. Zoroastrian and Christian influences were felt in the south, in Yemen.
The main deities were worshiped in the form of a tree or a bétilo (sacred stone). Some bétilos were taken and accompanied the nomads on the move. The Arabs rose shrines and sacrificed animals in his honor. Other religious practices included fasting and pilgrimage. It was believed also in the presence of djinn, spirits, some of whom had a malignant character.
The Arabs recognized a deity they called Al-lah, the creator all things, but he lacked the character attributed to him later by Al-lah Islam had three daughters: Allat, Manat ("Fate") and Al 'Uzza ("The Mighty").
The city of Mecca in the Hijaz, about 80 km from the sea, was the center of an annual pilgrimage made by the Arabs. In it stood a shrine, the Kaaba, where there was the Black Stone, probably a meteorite, which was the object of veneration. The pilgrims gave seven laps around it clockwise to clockwise. In the seventh century the city gained importance as an economic center: it controlled the caravan traffic crossing the Saudi. Because she spent the products that had been brought to Yemen from Abyssinia and India and were transported by caravans to the Mediterranean. A route that crossed from the Saudi Arabian Gulf towards Abyssinia was closed due to the conflict between Persia and Byzantium, which has increased the importance of Mecca.
Source : http://pt.wikipedia.org/wiki/Hist%C3%B3ria_do_Isl%C3%A3o