Shivering in the biting cold of the Boyana Church, you look at the 13th Century portrait of Desislava and you wonder if this image, painted 100 years before Giotto revolutionised medieval art, is truly the earliest Renaissance portrait in the world, or has Desislava (and the tourists around you) fallen victim of hype?

It's difficult to know, especially when your only source of information is the elderly gentleman who's been in charge of the Boyana Church for many years and without whom entering it is prohibited. He is there not only to prevent you from taking pictures inside this UNESCO World Heritage monument, but he persistently and with great aplomb tries to convince you that the European Renaissance started here, near Sofia, in the 13th Century, when an unknown master painted these amazingly realistic portraits of Desislava, her husband Sebastocrator Kaloyan, a charming young Jesus and so on and so fourth.

However, there is hardly a state in the Balkans that doesn't claim to possess medieval murals with astonishingly non-medieval features, predating the Italian Renaissance by at least a century. The so-called White Angel from the church of Mileševa Monastery in Serbia is one of the most famous examples. Others are the striking mosaics in the Chora Museum in Istanbul.

All of them, actually, are the product of the so-called Palaiologos Renaissance. This art movement appeared and flourished in the 13 and 14th centuries in Byzantium, and neighbouring states such as Bulgaria and Serbia, and even Russia. The artists of the period really did break free of some of the restraints of established medieval art, and when looking at murals or mosaics from that period you often stumble upon images of church patrons, saints and even Christ that look incredibly realistic.

The movement, however, never produced anything on par with the art of the Italian Renaissance. Whatever the truth, the Palaiologos Renaissance ended during the turbulent internecine wars between the Balkan states that paved the way for the Ottoman conquest of the peninsula in the 14 and 15th centuries. What is beyond any doubt, however, is that the 13th Century murals in Boyana Church are a striking example of Palaiologos Renaissance art, the best preserved in Bulgaria. They appeared during the second phase of the long and somewhat complicated history of the church.

The first church on this site was built at the end of the 10th or the beginning of the 11th Century: a humble domed structure of brick and mortar that still exists today. It is at the far end of your tour inside Boyana Church, and after restoration some of its murals can still be seen. In the 13th Century Sebastocrator Kaloyan, a member of the Bulgarian royal family and lord of Sredets, present-day Sofia, enlarged and repainted the church. Kaloyan lived with his family in a palace in the city and, like some of the present day nouveau riches, had a summer residence in the village of Boyana, at the foot of Vitosha mountain.