FACTBOX: The Olympic torch: peace, fraternity and controversy

(Reuters) - Security officials extinguished the Olympic torch at least twice on Monday during a chaotic relay through Paris where thousands of pro-Tibet protesters tried to block its path.

Here are some facts about the Olympic torch relay, and past and present controversies.

HISTORY OF THE FLAME:

* Flame races were run in ancient Athens to honor deities including Prometheus, who, legend has it, stole fire from the gods and brought wisdom and knowledge to humankind.

* A fire was kept burning at ancient Olympics to honor the sun god Zeus; but such races were not organized for the Panhellenic Games (four separate sports festivals of which the four-yearly Olympics were one).

* Fire first reappeared at the modern Olympics in Amsterdam in 1928, when a flame was built into an Olympic stadium tower. It was seen as a symbolic link between old and new games.

MODERN TORCH RELAYS:

* Foot races with torches were run at the 1894 international congress in Paris which decided to re-establish the Games.

* The first modern Olympic torch relay was introduced for the 1936 Berlin Games. More than 3,300 torchbearers carried the torch 3,190 kilometers (1,980 miles) from Olympia to Berlin.

* Athens' 2004 Summer Olympics saw the first global torch relay through 34 cities in 27 countries.

TORCH-LIGHTING CEREMONY:

* The torch is ignited several months before the games start at the ruins of Temple of Hera, in Olympia, southern Greece, site of the ancient Olympics. Actresses dressed as priestesses use the sun and a parabolic (curved) mirror to light the flame.

* Carried on foot to Athens in an urn, it is delivered to host city officials at the Greek capital's Panathinaiko Stadium. Shielded in a security lamp, it then travels on to the host city on foot, or via boat, airplane, bicycle, car or train.

RECENT TORCH CONTROVERSIES:

* 2000: The torch-lighting ceremony for the Sydney Olympics comes under fire for switching the first handover from a Greek-Australian girl to the 11-year old daughter of an International Olympic Committee member.

* 2006: Protests in Italy force torch bearers for Turin's Winter Olympics to change route four times during a two-month trip across Italy. Protesters voice opposition to U.S. corporate giant Coca Cola's sponsorship of the Games, U.S. First Lady Laura Bush's related visit and the construction of a high-speed railway from Turin to France.