The key to unlocking the Lebanese crisis may come down to a small plot of land, a badly drawn map, a softly spoken historian and some long-forgotten papers in an archive in Paris.

For almost 40 years, a stumbling point between Syria, Lebanon and Israel has been the ownership of a sparsely populated enclave called the Shebaa Farms, which sits on the border of the three states and was seized by Israel from Syria in the 1967 war.

US Secretary of State Condoleezza Rice has raised the Shebaa Farms as central to finding a long-term resolution to the conflict. Rice has reportedly asked Israel, which does not claim the land, to hand it over to the Lebanese Government as a goodwill gesture. The US believes this could bolster Lebanese Prime Minister Fouad Siniora, who would then be expected to call for an international force in southern Lebanon and assist with the disarming of Hezbollah.

The problem is that the land has been claimed by both the Syrians and the Lebanese — ever since French mandate officials began drawing lines between the two countries over an 1860s Ottoman-era map.

Since gaining independence in 1946, Syrian maps have included the land while Lebanese maps, and its 1000-pound note, put the territory in Lebanon.

To settle the dispute, negotiators have long sought proof to show that the land belongs to one side or the other. Four years ago, while rummaging through government archives in Paris, a historian at the Hebrew University in Jerusalem, Asher Kaufman, stumbled on documents that appear to resolve the dispute.

Kaufman, who bears a slight physical resemblance to Indiana Jones, discovered a set of papers from the French mandate era from 1920 to 1941 that show that French officials in the 1930s had accidentally put the Shebaa Farms in Syria.

The papers reveal that the officials realised their error and wanted to correct the maps, which had been drawn without surveyors or cartographic equipment, but the mistake was never fixed.

After Kaufman published his findings, an editorial in Lebanese newspaper the Daily Star chided the Lebanese academic community and claimed it was embarrassing that the discovery had been left to an Israeli researcher.

An Israeli journalist, Akiva Eldar, urged the UN to revisit its Lebanese resolutions.

"If the Lebanese or Syrians had reached the archives in Paris in time and presented the evidence that Kaufman found, the UN's decision would look very different," Eldar observed four years ago.

But Kaufman's findings were published two years after Israel's Lebanon pull-out in 2000 and were not considered by the UN team that investigated where to draw the border.

At the time, Lebanon presented the UN with a map from 1966 that showed the land was Lebanese, but it was later shown to be a forgery. Eventually, after examining almost 100 maps, the UN declared that "on all maps the UN has been able to find, the farms are seen on the Syrian side".

The Israeli withdrawal was rubber-stamped by the UN and the dispute over the Shebaa Farms put aside for future negotiations between Syria and Israel. But Lebanon never ceded its claim.

Israeli officials have long dismissed Hezbollah's claims to the territory as an excuse to attack Israel, but Prime Minister Ehud Olmert has this week reportedly expressed a willingness to return the land to the Lebanese Government.

Kaufman's papers, which may convince Syria to relinquish its claim, could be the key to peace.