By Peter Apps, Political Risk Correspondent
(Reuters) - Ancient Greek historian Herodotus divided Libya into four ethnic "nations." Some 2,400 years later, ethnic groups have shifted somewhat but tribal and cultural divisions could still prove key to how the struggle for power in Libya develops.
Below is a summary of some of the main tribal and regional divisions within Libya.
Coastal Libya has been divided into two distinct provinces since before the time of the Romans -- Tripolitania in the west around Tripoli and Cyrenaica around Benghazi.
The two provinces and their capitals have long had different cultures -- the west influenced by its Phoenician colonizers from modern day Lebanon and the east by the ancient Greeks.
Conflict seems to have divided Libya once again along those traditional lines, with the area around Benghazi apparently under opposition control and the rebels taking the flag of the former Cyrenaican monarchy ousted by Gaddafi.
While many Libyans -- particularly those in the opposition -- play down the East-West divide, outside analysts say anti-Gaddafi feeling was always higher in eastern areas.
Gaddafi is seen as having generally retained the support of his own tribe as well as southern Saharan tribes from Libya's old southern desert province of Fazzan and possibly others.
Political risk consultancy Stratfor estimates Libya has up to 140 tribes, but only 30 have any particular significance.
Below are some of the main tribes with details provided by analysts and Reuters reporters around the region. Tribal affiliations are seen as most important in rural areas.
Muammar Gaddafi's own tribe is one of Libya's smaller groups and not historically particularly powerful. With its territory the port of Sirte midway between Tripoli and Benghazi down into the Sahara, he has used it to help cement his position in power.
Analysts say the tribe has become wealthy, is sometimes accused of holding a monopoly of power and makes up the core elements of some of the "regime protection units."
Some reports suggest all air force pilots have to be members of the tribe -- which might point to some internal divisions. Some pilots have defected to Malta or ejected into the desert rather than bomb opposition targets.
Usually estimated to be Libya's largest tribe with up to one million of the total roughly 6 million population, tribal elders announced early on they were turning against Gaddafi.
The tribe is based primarily to the east of Tripoli with origins in Misrata, currently besieged by Gaddafi's forces. Some of their territory reaches toward Sirte. The tribe launched a coup against Gaddafi in 1993 with the support of the Magarha tribe demanding greater representation in government.
Although the coup failed and a number of leaders were killed, imprisoned and driven into exile the tribe have maintained sizeable numbers within the military. The tribe includes six subtribes and Gaddafi may look to exploit any divisions.
Believed the second largest tribe, they have long had mixed relations with Gaddafi's government. Originally from the interior, many have moved to the coast as the tribe has played an increasingly central role in politics. Leader Abdessalam Jalloud was once seen as perhaps the second most important man in the country, but he fell out with Gaddafi in the 1990s and the tribe joined the 1993 uprising.
After the failure of the coup, the tribe was able to maintain much closer relations with Gaddafi following closed-door negotiations.
The traditionally nomadic Tuareg are divided between a number of states in the Sahara whose borders they do not recognize. Analysts estimate just over 560,000 live within Libya. Tuareg rebels have attacked other Saharan governments and oil installations in pursuit of independence but have traditionally not clashed with the Libyan government, leading to some suspicions that Gaddafi has armed them in their fight elsewhere. Libyan officials have also offered asylum to non-Libyan Tuareg. They are believed broadly loyal to Gaddafi in the current conflict, although again details are sparse.
Gaddafi's second wife is from this eastern tribe and many of his children are believed to support it, with many members appointed to mid-level bureaucratic posts. While the east has largely gone over to the opposition, the tribal leadership do not appear to have made any overt statements as to their loyalty during the current crisis
Largely rural and living in oil-rich regions of the east and interior, the tribe is relatively small but might demand greater say in the use of oil revenues. They are reported to have been among the most vocal against Gaddafi during the reason uprising, and are said to be relatively well armed.
OTHER EASTERN TRIBES
The Misrata are said to be the largest tribe in eastern Libya, based around the town of the same name and the cities of Benghazi and Darnah. The al-Awaqir is most prevalent in the city of Al Bayda, and have long been at the center of opposition to Italian and Ottoman colonialism. The Obeidat are clustered around the north-eastern garrison town of Tobruk. Several senior officials from this group publicly defected at the beginning of the uprising.
OTHER WESTERN TRIBES
The Bani Walid overlap geographically with the Warfalla, and were reported to have defected from their units early in the uprising. The Tarhuna make up roughly a third of the population of the capital Tripoli, while the Zentan are located between Tripoli and the Tunisian border. Both tribes are said to be heavily represented the military but members were also reported to have joined early protests.
Sources: risk consultancies Stratfor, AKE, Reuters