Greece is upset that something very precious to its culture is displayed not in Greece, but in the British Museum in London. Greece wants these valuable art treasures back. So far the British are not budging.
The argument that has been raging on and off for a century is in the news once more because last month Greece officially asked Britain to return the Elgin Marbles.
The Elgin Marbles are actually one of the world's greatest collections of marbled sculptures. They consist of statuary and massive friezes. Friezes are large bands of artwork that run across the side of a building. They are usually ornamental or show a particular scene from life.
They were called Elgin Marbles after Lord Elgin, then the British ambassador to Turkey, brought the collection back from Greece to Britain between 1801 and 1803. Some records pinpoint the date as 1806. At that time Greece was part of the Ottoman Empire.
The Ottoman Empire was just another term for the vast Turkish Empire, which collapsed by the time World War I ended, in 1918.
The collection that Lord Elgin brought back to London and that was bought by the British Museum in 1816 was taken from the Parthenon, which overlooks Athens, the capital of Greece.
The Parthenon is a temple built by Pericles to the goddess Athena more than four centuries before Christ - between 437 and 432 BC. It is generally considered the greatest masterpiece of architecture in the world because of its perfect proportions and fine details.
Although they have been badly damaged over the centuries, the ruins of the Parthenon, standing on the hill known as the Acropolis, attract millions of tourists every year.
The fact that the Elgin Marbles, which came from the Parthenon, are displayed to tourists in London instead of Athens makes the Greeks angry. They believe these important treasures do not belong in a foreign country. Some people in Britain agree.
The reason Lord Elgin, who was a lover of antiquities (as ancient relics are called) wanted to move them was to help preserve them. The Parthenon had been badly damaged by war and the weather. The British believe the British Museum is a safe place for the Elgin Marbles, because they are protected there from any further outdoor pollution.
The Greek government won't accept that decision. It has the backing of a number of other countries - countries that believe they too have been robbed of great art treasures and would like them back.
The British government doesn't want to hand back the Elgin Marbles because it fears that once it did, there would be no end to demands from other countries to hand back antiquities they say belong to them. If that should happen, the museums of the Western world could become very empty places indeed.