PARIS: They were allies when Iran was ruled by the shah but became foes after its Islamic revolution in 1979, and now Israel considers Iran an "existential threat".
After Israeli strikes on Iranian targets inside Syria this week sent regional tensions soaring, here is a recap of their volatile relationship in the past half century.
Special relationship
On the creation of Israel in 1948, the shah of Iran, Mohammad Reza Pahlavi, establishes close ties with the new country. At the time, Iran is home to the biggest Jewish community in the Middle East.
Israel sets up a major diplomatic mission in Tehran and imports 40 percent of its oil from the country in exchange for weapons, technology and agricultural produce.
Iran's feared Savak secret police is created in 1957 with the help of the CIA and eventually Israel's Mossad.
Relations sour in 1979
The special relationship ends with the 1979 revolution that topples the shah, and Israel does not recognise the new Islamic Republic of Iran.
For the new authorities in Tehran, Israel becomes an "occupier" of Jerusalem and responsible for the "genocide" of Palestinians. Informal commercial links remain in place, however.
In 1980 the Iranian-inspired group Islamic Jihad becomes the first Islamist Palestinian organisation to take up arms against Israel, with Iran as its main financial backer.
Israel nonetheless provides about 1,500 missiles to Iran during the 1980-1988 Iran-Iraq war.
Iran-backed Hezbollah created
In 1982 Israel invades the Lebanese capital Beirut to put an end to attacks from Palestinian groups based there. It leads to the creation of the militant group Hezbollah at the initiative of Iran's elite Revolutionary Guards.
Hezbollah sets up in southern Lebanon, from where it wages a campaign against Israeli forces.
Israel blames Hezbollah for attacks on its interests abroad including in Argentina where the 1992 bombing of the Israeli embassy kills 29 people and a 1994 attack on a Jewish community centre leaves 85 dead.
'Wiped off the map'
In 1998 Iran says it has successfully tested for the first time its Shahab-3 missiles, whose 1,300-kilometre (780-mile) range means it could reach Israeli territory.
It announces another succesful test in 2000, alarming Israel which fears its enemy is developing a nuclear capacity.
In 2005 new hardline Iran president Mahmoud Ahmadinejad says Israel is doomed to be "wiped off the map" and that the Holocaust was a "myth".
This chimes with statements by Iran's supreme leader Ayatollah Ali Khamenei, who refers to Israel as a "cancerous tumour" that should be cut out of the Middle East.
When Iran resumes uranium enrichment activities at Ispahan the same year, Israel calls on the International Atomic Energy Agency (IAEA) and the United Nations to prevent it from acquiring nuclear weapons.
When the Iran nuclear deal is brokered by world powers in 2015, Israeli Prime Minister Benjamin Netanyahu slams it as an "historic mistake". He gives his full backing to US President Donald Trump's decision to retreat from the nuclear deal in May 2018.
Syria, a new battleground?
Officially still at war with Syria, Israel claims to be trying to keep out of the conflict since it broke out in 2011. But from 2013 it becomes wary of the role played by Hezbollah and Iran on the side of Syrian President Bashar al-Assad against rebels and jihadists.
"We will not allow Iranian entrenchment in Syria no matter the price to pay," Israeli Defence Minister Avigdor Lieberman says in April.
On Thursday this week, Israel launches strikes on suspected Iranian positions in Syria, prompting concern that Hezbollah could retaliate.
Alliance against Iran
In 2017 Netanyahu says Israel and leading Arab states see "eye-to-eye" on concerns about the growing influence of Iran in the region.
Israel's military chief of staff says later his country is prepared to cooperate with Saudi Arabia to face Iran's plans "to control the Middle East".
Saudi Arabia, a long-time foe of Israel, is the main religious and regional rival of Iran, with the two powerhouses also on opposing sides of conflicts in Yemen, Iraq and Lebanon.
In April, in a notable shift in the kingdom's position, the Saudi Crown Prince Mohammed bin Salman says Israel has a "right" to a homeland