Britain's Balfour Declaration turns 100 this week, hailed by Israel for helping lead to its founding, but viewed by Palestinians as contributing to a catastrophe that stole their land.
The November 2, 1917 declaration by then British foreign minister Arthur Balfour said his government viewed "with favour the establishment in Palestine of a national home for the Jewish people".
It was only one sentence of 67 words, but it was the strongest support yet from a world power for the goals of the Zionist movement -- Jews, including those facing persecution, resettling in the land of their ancient ancestors.
Israeli Prime Minister Benjamin Netanyahu will commemorate the anniversary in London, where he will attend a dinner in honour of the declaration with his British counterpart Theresa May.
May has said she will mark the date with "pride", but there is also criticism in Britain over the anniversary because of Israel's continuing half-century occupation of the West Bank.
Opposition leader Jeremy Corbyn of the Labour party has said he cannot attend the dinner -- without explaining further -- although shadow foreign secretary Emily Thornberry will.
Palestinians are planning a demonstration on Thursday in Ramallah as part of their campaign calling on Britain to apologise for the declaration. They have also explored suing Britain over it.
Netanyahu said this week that the declaration "advanced the international moves that established the state of Israel".
"While the state would not have arisen without settlement, sacrifice and a willingness to fight for it, the international impetus was, undoubtedly, the Balfour Declaration," he said.
For Palestinian prime minister Rami Hamdallah, Britain should apologise for a "historic injustice it committed against our people and to correct it instead of celebrating it".
"The international community is obliged, while we approach the first centennial of the ominous Balfour Declaration, to end the historic injustice that has been inflicted on our people."
The declaration came in a letter from Balfour to Lord Walter Rothschild, a leader of the Jewish community in Britain, and had British cabinet approval.
Some argue today that later events -- conflicting policies from Britain and the Zionists' own efforts to realise their dream -- diminished the Balfour Declaration's importance.
But others see it as monumental, having helped lay the groundwork not only for the creation of the modern state of Israel, but also the Israeli-Palestinian conflict.
"It's dramatic," Jonathan Schneer, an American historian and author of the book "The Balfour Declaration", told AFP.
"And they're both right," he said, referring to the starkly different viewpoints of Israelis and Palestinians.
"The Israelis see it as a foundation stone for the birth of a Jewish state, and the Arabs see it as a foundation stone leading towards their dispossession and misery."
According to Schneer, the declaration ironically grew to a large degree out of anti-Semitic myths.
British leaders saw the Jewish community as capable of helping them win World War I due to its perceived influence in finance and within Russia, he said.
Others say that Britain was also seeking a firm foothold in the Middle East after the war.
But regardless of the motivations that created it, "if someone has to choose five documents that shaped Israel's history and existence, then the Balfour Declaration has to be one of them", said Paula Kabalo, director of Israel's Ben-Gurion Research Institute for the Study of Israel and Zionism.
For Palestinians, the declaration is colonialist and even racist.
It mentions that "nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine".
Not only were they left nameless in the document, Palestinians say, but Britain has also failed to ensure the pledge was maintained.
It was written "as if the Palestinians did not exist", said Nabil Shaath, a senior adviser to Palestinian president Mahmud Abbas.
"We were referred to as 'others', others in Palestine who had civilian and religious rights but no political rights whatsoever."
It would be another 31 years before the state of Israel would be founded in 1948.
The war surrounding its creation saw 750,000 Palestinians either expelled or fleeing from their homes.
In the Six-Day War of 1967, Israel occupied the West Bank, east Jerusalem and the Gaza Strip. It later annexed east Jerusalem, which the Palestinians want as the capital of their future state.
Hopes for a two-state solution to the Israeli-Palestinian conflict are greatly diminishing as Israeli settlement building continues in the West Bank.
Britain's May sought to acknowledge those concerns in her recent comments.
"We are proud of the role that we played in the creation of the state of Israel and we will certainly mark the centenary with pride," she said.
"We also must be conscious of the sensitivities that some people do have about the Balfour Declaration, and we recognise that there is more work to be done. We remain committed to the two-state solution in relation to Israel and the Palestinians."