Until recently, the flag of Libya held a special place in the hearts of vexillophiles as The World's Most Boring Flag. That's because it was nothing but a green rectangle, with no markings of any kind.

But starting in February, a new flag – red, black, and green with a white star and crescent in the center – has been hoisted at Libyan embassies around the world, from Switzerland to Bangladesh. It is the same flag being flown by the jubilant rebels themselves as they descend on Tripoli.

So what's the deal with this new flag? Is there a Libyan Betsy Ross among the rebels? Where did it come from?

The new flag is actually a retro flag. It's the flag of the Kingdom of Libya, which existed from 1951 to 1969, until a group of military officers led by Col. Muammar Qaddafi overthrew the government. The rebel National Transitional Council is calling for the establishment of a republic, but many of the rebels have been seen displaying photos of the country's first and only king, Idris of Libya, who died in exile in 1983.

Before independence, Libya was governed by the Allies, the Italians, and from the 15th century to 1911, the Ottoman Empire.

The Kingdom of Libya's flag is based on the flag of the Emirate of Cyrenaica, a region in eastern Libya that in 1949 unilaterally declared independence from the Allies under King Idris, who then went on to unite it with the country's other two historical regions, Tripolitania and Fezzan.

Cyrenaica's flag was black with a white star and crescent. When Libya gained independence from the Allied forces in 1951, King Idris added a red stripe at the top to represent the blood of Libyans who died under Italian fascist rule, and a green stripe at the bottom to symbolize independence.

Upon taking power in 1969, Qaddafi renamed the country the "Libyan Arab Republic" and replaced the country's flag with a red, white, and black horizontal tricolor. In 1977, he changed the name of the country again, this time calling it the "Great Socialist People's Libyan Arab Jamahiriya." ("Jamahiriya" is a word coined by Qaddafi and often left untranslated. It roughly means "state of the masses" or "peopledom.")

For the flag of this newly renamed state, Qaddafi opted to go monochrome. Green is the traditional color of Islam, traditionally the favorite color of the Prophet Mohammed, and a powerful symbol of life for people living in the desert. The color also complements the Green Book, Qaddafi's 1975 collection of musings and aphorisms on everything from economics to the biological differences between women and men, which all Libyan schoolchildren were required to study for at least two hours a week.

Qaddafi's green flag is not unprecedented: It was also the banner of the Fatimid Caliphate, which ruled over North Africa, including what is now Libya, from 909 to 1171. Like that flag, it seems that Qaddafi's green flag will soon become little more than a historical curiosity.