Ayatollah Ruhollah Khomeini’s Iranian rebels established ties with Palestinian leaders years before the 1979 Islamic Revolution. Anti-Semitism and ideological anti-Zionism drove Khomeini’s opposition to Israel’s existence. Khomeini also saw that the Palestinian cause’s centrality to the Arab world could serve as a gateway for him to spread his revolutionary ideology to the otherwise unreceptive and predominantly Sunni Arab street.

Khomeini found a willing partner in Yasser Arafat, the founder of Fatah, chairman of the Palestine Liberation Organization (PLO), and de facto leader of the Palestinian nationalist movement. Arafat considered Khomeini a tool to turn Iran against Israel and thereby deprive the Jewish state of one of its most important regional—and few Muslim—allies.

When Khomeini dispatched a follower in 1973 to establish alliances in the Muslim world, Arafat was receptive. Arafat met with Khomeini at least twice in the latter’s residence in exile in Iraq, and agreed to train the ayatollah’s supporters at Fatah’s bases in Lebanon.

Between 1976 and 1978, Fatah trained Khomeini’s revolutionaries in Lebanon and provided funds, guidance, and equipment. Fatah effectively created and tutored the nucleus of what would become the Iranian regime’s Islamic Revolutionary Guard Corps (IRGC) and intelligence apparatuses.

By 1977, Fatah had trained more than 700 of Khomeini’s fighters, including the cleric’s two sons Mustafa and Ahmad. Many of these Iranian graduates—including Ahmad, who became an honorary Fatah member—participated in Fatah’s assaults against Lebanese Christian factions.

Arafat also developed a personal relationship with Khomeini, sending him a condolence letter when Mustafa died in 1977. In return, when Khomeini came under pressure from Saddam Hussein in 1978, the ayatollah considered seeking refuge among Arafat’s Palestinian militias in Lebanon’s Bekaa Valley, but eventually moved to France.

Fatah directly and indirectly aided Iran’s Islamic Revolution, with one Palestinian official even boasting in 1978 over the PLO’s role in “fomenting trouble in Iran.”Senior Fatah operative Hani al-Hassan directed the Khomeini forces’ intelligence efforts. (Al-Hassan went on to command Khomeini’s bodyguards immediately after the cleric’s return to Iran, and Arafat named him the PLO’s first ambassador to the Islamic Republic.)

In August 1978, bands of heavily armed, Palestinian-trained men engaged the shah’s forces, killing five policemen. Palestinians may also have helped instigate the revolution’s “point of no return,” the “Black Friday” massacre by the shah’s forces of protesters at Jaleh Square on September 8, 1978. Investigations into the incident turned up evidence that Palestinian gunmen may have provoked the bloodbath by firing on soldiers from within the crowd.

As the revolution escalated, Shah Mohammad Reza Pahlavi fled Iran on January 16, 1979, paving the way for Khomeini’s return to the country two weeks later. Khomeini quickly requested Arafat’s help in forming an Islamist government. The ayatollah promised that once he had consolidated his grip on the new regime, he would “turn to the issue of victory over Israel.” Arafat welcomed the revolution’s success, viewing it as a turning point in the Palestinian struggle against Israel, and arrived in Tehran on February 5 with a 31-member Fatah and PLO delegation. The group included many of the best-trained commandos of Fatah Force-17, Arafat’s personal security service, whom he assigned to protect Khomeini.

Khomeini’s opponents claimed that significant numbers of Palestinian militants remained in Iran well after the revolution—“over 20,000,” according to former Iranian Prime Minister Shahpour Bakhtiar. Others claimed Palestinians were piloting the new regime’s air force or were present among the militants who seized the U.S. embassy in Tehran. A 1980 Central Intelligence Agency (CIA) memorandum indicated that about half a dozen PLO-linked Palestinians remained in Tehran to train the nascent IRGC.

Despite Fatah’s assistance in toppling the shah, Khomeini’s regime quickly subordinated the Palestinians to Iran and usurped their cause.

Arafat first attempted to exploit his ties with Khomeini. During the Iran hostage crisis, he used his ties to the ayatollah in a bid to act as an intermediary for the release of the American hostages, and thereby obtain recognition from the United States. Khomeini objected, however, and Arafat withdrew his offer, demonstrating the limits of his influence on the ayatollah.

Likewise, after Israel invaded Lebanon in 1982 and destroyed the PLO’s stronghold in Beirut, and as the Iran-Iraq War was raging, the PLO recommended that Khomeini accept an Iraqi proposal for a ceasefire and join the battle against Israel. The ayatollah rejected this counsel, proclaiming that the “road to Jerusalem passes through [the Iraqi city of] Karbala!” Khomeini showed again that Iran—not the Palestinians—dictated the terms of their relationship.

Tehran soon showed it would not treat its onetime Palestinian patrons as equal partners. The CIA estimated that Khomeini’s regime intentionally kept the PLO’s presence in post-revolution Iran “relatively limited” in order to “prevent the Palestinians from playing a significant role in Iran’s internal affairs.” Though Khomeini invited PLO fighters to train the newly-formed IRGC, these Palestinians ended up playing “little role in the formation of the Guards because many Iranian officials including regular military advisors feared that the Palestinians would gain too much influence in the Iranian military.”

As his regime matured, Khomeini continued to exploit his relationship with the Palestinians to further Tehran’s regional interests. At a November 1979 PLO solidarity conference in Lisbon, one of Fatah’s first Iranian graduates, Mohammad Montazeri, vowed to recruit 100,000 Iranian volunteers to fight Israel on behalf of the Palestinians. This pledge appeared on its face to fulfill Khomeini’s promise to begin joining the Palestinian fight against Israel, but Iran had other intentions.

A month later, the first 400 Iranian volunteers arrived unannounced in Damascus. Rather than join one of the several Palestinian factions operating in Lebanon, however, they declared their intention to travel to Lebanon to establish a Shiite movement, chanting slogans like “Today Iran, tomorrow Palestine.” Instead of seeking to liberate Palestine, they were exploiting the Palestinian cause to spread Iran’s revolution. These efforts would soon culminate in Iran’s formation of Hezbollah in Lebanon.

The Islamic Republic’s ties with Fatah and the PLO soon began to deteriorate, particularly in the late 1980s as Arafat signaled his desire for détente with Israel. As relations between Tehran and Arafat soured, Imad Mughniyeh— Hezbollah’s future storied commander who began his terrorist career as Arafat’s bodyguard in Fatah’s Force-17—stepped in to act as a conduit between his old mentor and Iran and Hezbollah. Mughniyeh had become disillusioned with Fatah after the PLO’s defeat during Israel’s invasion of Lebanon, and soon defected to the IRGC. Mughniyeh nonetheless maintained contact with Arafat and other Palestinian factions, even after their expulsion from Beirut to Tunisia in 1982.

In early 1988, Mughniyeh traveled to Tunisia to meet with Arafat. Arafat briefed Mughniyeh on impediments to the West Bank activities of Khalil al-Wazir—aka Abu Jihad, the PLO’s military chief and Arafat’s top aide, who was managing the intifada. Mughniyeh then returned to Beirut and dispatched Ali Deeb—aka Abu Hassan Khudur Salameh, once Mughniyeh’s former commander in Fatah—to Tunisia to meet with Arafat. Deeb tried to convince Arafat to cease negotiations with the Israelis and instead move to Tehran and continue the struggle against Israel from there. Mughniyeh’s goal was both to undercut reconciliation between Israel and the Palestinians, and to transfer the center of the Palestinian nationalist movement from the Arab world to Iran.

Arafat declined Deeb’s offer, fearing Arab states would “kill him,” but Deeb did not relent. He accompanied Arafat to the Sixth Arab Summit Conference in Morocco in 1989, and attended his meetings with Arab leaders. Deeb reported back to Mughniyeh that there was no chance to “liberate Palestine” under Arafat’s leadership. Mughniyeh soon convinced Deeb to leave Fatah and join Hezbollah, with Arafat’s blessing. Deeb would prove critical to Mughniyeh’s plans to weaponize the Palestinian cause until the former’s assassination by Israel in 1999.

Apparently influenced by Deeb’s disillusionment with Arafat, Mughniyeh turned his attention to Arafat rival Abu Jihad, with whom Mughniyeh reportedly had a “close relationship” from their Fatah days. Mughniyeh began corresponding directly with Abu Jihad, and secured funds from Tehran for his operations in the West Bank and Gaza. As with Arafat, Mughniyeh began advising Abu Jihad to move from Tunisia to Iran and lead the fight against Israel from there. Abu Jihad hesitated, but soon relented and planned to relocate, until Israel assassinated him in April 1988.

In December of 1988, Arafat announced the PLO’s recognition of Israel, signaling his pursuit of a peace agreement with the Jewish state. Mughniyeh again stepped up efforts to undercut his old mentor and bring the Palestinian national movement under Iran’s aegis. He asked yet another Palestinian leader, Salah Khalaf (aka Abu Iyad), the head of Fatah’s central security, to relocate to Tehran. Khalaf agreed but, like Abu Jihad, was assassinated in Tunisia in 1991.

In the early 1990s, a former Fatah leader close to the IRGC visited Arafat in Tunisia and advised him to improve relations with Iran and Hezbollah. Arafat responded that the Arab countries would cut him off if he did, but expressed readiness for improved ties with Hezbollah, asking for Mughniyeh to be the go-between. While Hezbollah and Iran officially cut off contact with Arafat after he signed the Oslo Accords in 1993, Mughniyeh maintained his ties and continued trying to increase Tehran’s influence over Arafat and the PLO.

In 1996, Hezbollah’s leadership met in Iran and established a “Palestine Unit” with the duty of working within Israel, the West Bank, and Gaza. Mughniyeh would later tell Palestinian contacts that the unit would not replace Palestinians themselves in fighting Israel, but would “provide for all of the necessities to support the resistance fighters in Palestine…to push out [the Israelis] gradually.” Mughniyeh tasked Ali Deeb with this portfolio and with communication with the Palestinian factions. Gone were the days when the Palestinians lavished support on Iran’s nascent revolutionaries. Tehran now assumed the upper hand—and has used the Palestinian cause as a tool for regional expansion ever since.