In the fateful year of 681, the Bulgarian Khan Asparuh probably had no idea that he would be laying the foundations of the future Bulgarian state. The only thing that he must have known at the time would have been that he had successfully led his people across the Danube. He had defeated the Byzantine Empire on its own territory and had to deliver the news of his victory to the rest of the Bulgars waiting on the northern bank of the river. He did so by sending a carrier pigeon. But while the bird was still in flight, the Byzantines intercepted it and shot arrows into it.

In spite of its wounds, the pigeon arrived at its destination and achieved its purpose. Asparuh's sister was so happy with the news that she took the bloodstained white thread that had secured the letter to the bird's leg, cut it into strips and decorated her brother's warriors with the pieces. In her opinion, her newly invented amulet would bring them victory, health and happiness.

Ever since then the khan's descendants decorate themselves and their relatives with red and white threads called martenitsa on 1 March.

This is only one of several patriotic legends about the symbolism of the martenitsa. It probably appeared in the 19th-20th centuries and has been hammered into children's heads ever since. The topic is covered in a number of websites, including Wikipedia.

The romantic story of the Bulgarian khan is the apotheosis of the more mundane interpretation of tradition, which makes  Bulgarians wear the martenitsa as a symbol of spring, and of their hopes for good health and luck throughout the year. Under the Communist regime, the first plastic martenitsi, in the shape of storks, tulips or snowdrops, appeared, replacing the more traditional red and white dolls representing the two folk characters Pizho and Penda.

Democracy reinforced this tendency. As early as the middle of February, it would be impossible to walk down any major Bulgarian street and not stumble upon a martenitsa stand. Some of them sell crochet-hook martenitsi and the traditional interwoven red and white threads, with or without the usual blue bead to ward off the evil eye. Most of them are made by the sellers or their relatives and range from kitsch bracelets with your name on them to huge wreaths to hang on your front door.

Plastic amulets, however, reign supreme. Some are made in the images of Batman, Barbie, Spiderman and other popular cultural idols. Others represent Yin and Yang. In 2005, after the first "Big Brother" TV series in Bulgaria, the citizens of Pernik literally went mad for martenitsi bearing photographs of the people who had participated in the show. Singer and TV personality Azis and footballer Berbatov have also been turned into martenitsi symbols.

The holiday itself has become an occasion for social activities. A few days before 1 March, politicians and mayors visit nursing schools and homes for disabled children, and tie red and white threads, though mainly to get their photos in the press. In 2002, a woman from Stara Zagora entered the Guinness Book of Records with her 12-metre martenitsa. Since then, others have tried to beat her achievement.

However, Bulgarians recently learned a horrible truth about their martenitsi. Whether plastic or woollen, most of them are made in China. In spite of its ancient origins, the martenitsa has now become a part of the global economy.

Evidence that the martenitsa is older than proto-Bulgarians or Khan Asparuh himself is purely circumstantial. But, like Dan Brown's novels, it makes for a more exciting tale.