Later this month a team of Hungarian researchers will publish a report on the whereabouts of the heart of one of Ottoman Turkey's most famous sultans. But why has this become such an important historical riddle to solve?
The French statesman Cardinal Richelieu described it as "the battle that saved civilisation" - the siege of the Hungarian castle of Sziget, 447 years ago, almost to the day.
The Muslim Turks finally took the town in September 1566, but sustained such losses, including the death of their leader, Sultan Suleiman the Magnificent, that they did not threaten Vienna again for 120 years.
Now researchers are digging in the soil - and the archives - for the good sultan's heart.
"When Hungarians walk through the grounds of the castle in Szigetvar they imagine they are walking through a Hungarian castle. But of course, that is not true," says Norbert Pap, Professor of Geography at the University of Pecs, as we stroll along the beautifully restored brick ramparts.
He smiles. "This is in fact the Turkish castle. The Hungarian one was destroyed in the siege of 1566."
Like the rolling hills of the surrounding Zselic region, each fold of history concerning that siege and what followed, seems to conceal another. And each substitutes another version of events.
On the surface the legend is easy to follow.
Suleiman the Magnificent arrived here with up to 100,000 crack Ottoman troops in early August 1566.
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The castle was on his route to Vienna, which he confidently expected to capture, and thus pave the way for the addition of great chunks of Western Europe to his dominions.
The air trembled to the beat of the big war drums - made, as they still are today, in the handsome city of Edirne. I once bought one there for my son.
But Miklos Zrinyi, the commander of the castle, and his garrison of only 2,300 men put up such a brave fight that the Turks were stopped in their tracks.
Zrinyi died in the final sortie from the burning castle.
Suleiman died in his tent - some sources say from surprise at his Pyrrhic victory. He was 72, after all, and had been fighting the Hungarians for 40 years.
His body was taken back to Constantinople, but his heart was buried here, in a tomb which subsequently became a Catholic church, dedicated to the Virgin Mary, or so reads the inscription on the Turbeki church, just east of the town.
But that's just a fairy story, Prof Pap explains. The plaque was put there in 1916 by the local priest, for political reasons.
At that time Hungary - or the Austro-Hungarian Empire - was an ally of Ottoman Turkey, two ancient empires stumbling to their ruin in the mud and blood of World War I, and they needed symbols of undying friendship.
Now Prof Pap has been tasked with finding the true burial place of Suleiman's heart, also for political reasons.
Relations between Hungary and Turkey are enjoying a big revival.
Who was he?
Sultan Suleiman I, born 1494, died 1566
Known as the Magnificent, or the Lawgiver on account of his creation of a legal code which lasted hundreds of years
He ruled the Ottoman Empire when it was at its most powerful militarily, its richest and most culturally influential
When he died, the empire stretched into parts of North Africa, the Balkans and present-day Hungary
The two prime ministers get on well. The number of Turkish tourists visiting Hungary has leapt by 45% in the last year.
But there are only 500 beds in this sleepy town, where tens of thousands once slept in tents, listening to the nightingales, preparing for battle.
At stake are a five-star hotel or two, and the further restoration of the castle and a host of Ottoman-era monuments. But everything hinges on finding the resting place of Suleiman's magnificent heart.
There are several maps. One from 1689 even marks the supposed burial place. Others in the war archive in Vienna were prepared for the Habsburg troops who retook the town in the 1680s.
Suleiman had already laid siege to Vienna in 1529
There is more information in the archives of the Vatican, in Venice, in Budapest, and in Istanbul.
There is more information in the archives of the Vatican, in Venice, in Budapest, and in Istanbul.
