Unlike churches, mosques have no denomination and all Muslims of every sect are welcomed to attend services at any mosque.
Sunni
They are considered the more orthodox Muslims.
Shiites
The term is a short version of Shi'at Ali, "the party of Ali." At
the time of Ali's death in 661AD, they were the party who supported his claim
to the Caliphate.
Sufis
They represent the mystical tradition in Islam in contrast to the mainstream
of Islam that, in its first centuries, was more concerned with expansion and
organisation of its community.
Kahrijites
In Arabic the word means, "to go out." The Kahrijites were the first
dissident and rebel Muslims. Like later dissidents, they chose to separate
from the main body because they believed that the majority of Muslims had
lost "the true path."
Wahhabis
They follow a strict traditionalist doctrine. They are mainly found in the
Arabian Peninsula. Muhammad ibn Abd al-Wahhab was the first modern Islamic
fundamentalist. He believed that all idea added to Islam after the third century
of the Muslim era was false and should be rejected.
Ismailis
Initially were part of the Shiite sect but they split from it because they
disagreed over who should be considered the next Imam.
Zaidis
Zaid, a grandson of Husain, created this sect.
Fatimids
They are a successor movement to the Ismailis and see themselves as descendants
of Fatima and Ali through the line of Isma'il. In the tenth century they asserted
themselves as caliphs of North Africa and ruled Egypt from 969 to 1171.
Nizari.
This sect is better known under the name of "the Assassins."
Alawis
The members of this sect are also known as "Nusayris." They are
a branch of Ismailism, but their doctrine has gone so far that many Muslims
do not regard this sect as still part of Islam. The word Alawis means "followers
of Ali", a term that in some countries refers to the Shiites in general.
They are accused of worshipping Ali as a God, but this is not really true.
Druze
This is another sect that is not widely regarded as truly Muslim. It diverged
from mainstream Islam in the 11th century when some Ismailis began to believe
that God became manifest in the personality of a prophet or an Imam.
Baha'i
This is also a sect that descends from Islam but it is not now regarded as
Islamic anymore.
PS:
The "Assassin sect" was not mentioned here although it was a well-known
Islamic sect. It was, in fact, the first known terrorist organisation whose
members were Persian and Syrian Shiite. It is a strange coincidence that the
two regimes accused of sponsoring terrorism today -Syria and Iran- are both
run by Shiite governments. Will the fall of Saddam Hussein in Iraq results
in another Shiite-led government sponsoring terrorism in Iraq? President Chirac
of France gave this as a reason not to participate to the invasion of Iraq
in 2003. Perhaps he was right and the Americans and the British were wrong!
The Assassin sect, a sub-sect of the Ismailis, was founded in Cairo, Egypt, in 1090 by the Persian Hassan Ibn al Sabbah. At that time the Muslim world was dominated by the Shia Fatimid dynasty but it soon lost power afterwards. The last Fatimid stronghold was in Cairo and al Sabbah made an alliance with the Sultan's son and heir, Nizar, to put back the Shiite in power. The members of this sect were called Nizaris. After the murder of Nizar al Sabbah returned to Persia to live a very secluded life in a castle. Young Nizari members were indoctrinated in al Sabbah's strict religion, brainwashed with the promise of immediate entry in heaven if they died following al Sabbah's orders. Al Sabbah relied on terrorism to put back the Shiite in power. The trained recruits called "fida'is" -self-sacrifying devotees- were used to kill the victims chosen by the sect's leaders. The killings were to take place in public to drawn attention on the sect although if this meant also the dead, in most cases, of the Assassins.
The Assassins reached their greatest notoriety in the 12th century when they
were drugged before being sent on their violent missions. They became known
in Arabic language as the "Hashasheen" -the smokers of hashish.
The crusader distorted the Arabic word and this explains why they were known
by the name "Assassins." Their reputation was so fearful that many
kings and emperors of the time made some kind of alliance with them. And they
hired them to destroy their enemies. The sect lasted until 1260 when the Mongol
Emperor Hulaga invaded Asia to take Damascus and eliminating the Assassins.