Less than three years ago Shimon Peres addressed the Turkish Grand National Assembly - Turkey's parliament - in Ankara.
It was the first time an Israeli president had addressed legislators in a Muslim country, a gesture which spoke volumes about the extraordinary relationship between Israel and Turkey, a relationship dating back to the early Turkish recognition of the Jewish state in 1949.
Uniquely among Muslim countries in the region, Turkey has strong trading ties with Israel.
The Turkish military buys weapons from Israel and trains with its armed forces, and in 2008 Turkey played host to more than half a million Israeli tourists, making it their favourite overseas holiday destination.
What has gone wrong?
Over the past 18 months the two countries have lurched from one diplomatic crisis to another, culminating in the furious Turkish response to Israel's raid on the convoy of ships trying to reach Gaza.
All military co-operation has been frozen, and Israeli tourists are cancelling planned trips to Turkey.
And now thousands of Turks have furiously besieged the Israeli consulate in Istanbul with choruses of "Allahu Akbar", and carrying posters with venomous messages of hatred toward Israel.
"We should cancel all our agreements," a young man called Bunyamin told me. "Israel can never be our friend - it's our greatest enemy."
Events in Israel and the Palestinian territories are part of the explanation.
Sense of betrayal
The Israeli operation against Gaza at the end of 2008 provoked widespread anger around the world, but the reaction from Turkey was stronger than most.
Prime Minister Tayyip Erdogan famously stormed off the stage at the World Economic Forum in Davos, accusing an astonished President Peres, who had been sharing the platform with him, of "knowing well how to kill".
It turned Mr Erdogan into an instant hero in many Arab cities, but also back home in Turkey.
Lashing out at Israeli injustice looked like a vote-winner.
As it happens, Mr Erdogan's outburst was partly driven by a sense of personal betrayal, say Turkish officials.
For weeks before the Gaza operation he had been patiently mediating between Israel and Syria, even at one point sending out an aide to buy a cigar at the request of the Israeli Prime Minister Ehud Olmert, despite being a passionate anti-smoker.
He felt he was earning the trust of both countries. But when Israeli forces launched Operation Cast Lead, Turkey got no advance warning, and Mr Erdogan felt badly let down.
The bigger picture, though, is the change in Turkish society, a change which has been going on for decades.
After the declaration of the Turkish republic by Mustafa Kemal Ataturk in 1923, displays of Islamic piety were strongly discouraged as inimical to Ataturk's modernising mission.
Turkey's secular state institutions, including the powerful military, have long had the upper hand.
But in recent years devout Muslims have felt a lot more comfortable showing their piety, most visibly in their clothing, like women's headscarves, and organising themselves with like-minded Muslims.
They have become a powerful constituency - around half the population considers itself devoutly religious.
They have helped win Mr Erdogan's Justice and Development Party a record two majorities in parliament.
And he considers himself one of them; a man who openly admits he feels far more comfortable mixing with Muslims than non-Muslims.
The Turkish charity IHH, which led the latest attempt to break the blockade of Gaza, has thrived on these changes in Turkish society.
Founded in the 1990s, it involved itself in the big Islamic causes of the day, like assisting Muslims caught in the conflicts in Bosnia and Chechnya.
At times its activities aroused the suspicion of the Turkish authorities, and it has been accused by Israel of openly supporting militant Islamic movements such as Hamas and the Muslim Brotherhood.
But its energetic championing of the Palestinian cause, in particular the plight of people in Gaza, has struck a chord with many Turks.
A large crowd gathered beside the Bosphorus to see off the Mavi Marmara, the ship the IHH chartered to lead the convoy to Gaza, and it was widely covered by the Turkish media.
So when news of the violent confrontation with Israeli forces on board the ship came - a confrontation filmed by Turkish journalists - the shock was widely felt here.
The Turkish government gave no official support to the convoy, but made it clear it backed the IHH mission.
Foreign Minister Ahmet Davutoglu said he had been trying through diplomatic pressure to get the convoy through to Gaza.
Many Turks believe the IHH gets plenty of unofficial support from sympathisers within the governing party.
The result is that Turkey finds itself embroiled in the most serious diplomatic rift with Israel in their shared history, with Turkish citizens believed to make up most of the dead and injured.
It is the dramatic culmination of a steady downgrading of relations with Israel, as Turkey has sought warmer ties with its once estranged neighbours, Syria, Iraq and Iran.
But it is also the culmination of changing attitudes in Turkish society, a large part of which is now more overtly Islamic in its identity and its view of the world than at any time in the country's 87-year history.