VATICAN CITY (AP) — The Knights of Malta, one of the most peculiar organizations in the world, marked its 900th birthday Saturday with a colorful procession through St. Peter’s Square, a Mass in the basilica and an audience with Pope Benedict XVI, himself a member of the onetime chivalrous order drawn from Europe’s nobility.

The Knights are at once a Roman Catholic religious order, an aid group that runs soup kitchens, hospitals and ambulance services around the globe, and a sovereign entity that prints its own passports and enjoys diplomatic relations with 104 countries — yet has no country to call its own.

Some 4,000 people — volunteers in neon orange civil protection suits, children in red berets and members each draped in a black cloak with a white, eight-pointed Maltese Cross on the front — processed through St. Peter’s Square and into the basilica for the Mass marking the 900th anniversary of the order’s recognition by the Holy See.

After the Mass, which was celebrated by the Vatican No. 2, Benedict came to the basilica for an audience during which he thanked the order for its service and urged it to continue providing health care for the world’s neediest while staying true to its Christian ideals.

The order’s work, he said, "is not mere philanthropy but an effective expression and a living testimony of evangelical love."

The order traces its history to an 11th century infirmary in Jerusalem set up by a monk to care for pilgrims visiting the Holy Land. During the Crusades, as the order’s humanitarian efforts spread, it took on a military role to protect pilgrims and Christendom as a whole from Muslim attacks. In February 1113 Pope Paschal II recognized the order with a papal bull establishing its sovereign status by saying it was independent of both lay and other religious authorities.

During its heyday, would-be members had to prove nobility through all eight great-grandparents. Such requirements are now largely relaxed except in some European countries. Still, the order’s members are drawn from some of the world’s wealthiest Catholics, who fund its health clinics, homeless shelters and old folks’ homes in 120 countries and rally for special appeals when disasters strike.

Sixty of the 13,500 members are so-called "professed knights," who make vows of poverty, chastity and obedience and live like monks, albeit without being ordained priests.

The order’s international legal status is entirely unique, a sovereign entity that prints its own stamps, coins, license plates and passports, yet has no territory over which it rules. Its forces once occupied Cyprus, Rhodes and Malta, but Napoleon expelled the order from Malta in 1798, depriving it of the final patch of land ove it ruled.

Nevertheless, the order still enjoys many of the trappings of a small country: U.N. observer status and diplomatic relations with 104 countries, most of them in the developing world where such ties can smooth the delivery of humanitarian aid. But the United States, for one, has no relations, precisely because it’s a stateless state.

In his speech Saturday, Benedict affirmed the sovereign status that the order enjoys. He acknowledged its peculiar nature, saying the order’s guiding spirit "aims not to exercise power and influence of a worldly character, but in complete freedom to accomplish its own mission for the integral good of man, spirit and body … with special regard for those whose need of hope and love is greater."

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