Hassan Nasrallah, the longtime leader of Hezbollah, was killed in a massive Israeli air attack on Beirut on Friday evening, the Lebanon-based group has confirmed.

The Israeli army had claimed the assassination earlier in the day.

Nasrallah, who reached the peak of his popularity after the war with Israel in 2006, was seen as a hero by many, not just in Lebanon but beyond. Standing up to Israel is what defined him and his Iranian-backed group, Hezbollah, for years. But that changed when Hezbollah sent fighters to Syria to crush the uprising threatening President Bashar al-Assad’s rule.

Nasrallah was no longer seen as a leader of a resistance movement but the leader of a Shia party fighting for Iranian interests, and was criticised by many Arab countries.

Even before Hezbollah’s involvement in the war in Syria, Nasrallah had failed to convince many in the Sunni Muslim Arab world that his movement was not behind the 2005 assassination of Lebanon’s former prime minister, Rafik Hariri. An international tribunal indicted four members of the group for the murder and one was later convicted.

Despite this, Nasrallah continued to enjoy support from his loyal base – mainly Lebanon’s Shia Muslims – who revered him as a leader and religious figurehead.

Born in 1960, Nasrallah‘s early childhood in East Beirut is cloaked in political mythology. One of nine siblings, he is said to have been pious from an early age, often taking long walks to the city centre to find second-hand books on Islam. Nasrallah himself has described how he would spend his free time as a child staring reverently at a portrait of the Shia scholar Musa al-Sadr – a pastime that foreshadowed his future concern with politics and Shia communities in Lebanon.

In 1974, Sadr founded an organisation – the Movement of the Deprived – that became the ideological kernel for the well-known Lebanese party and Hezbollah rival, Amal. In the 1980s, Amal mined support from middle-class Shia who had grown frustrated with the sect‘s historic marginalisation in Lebanon, to grow into a powerful political movement. Besides commandeering an anti-establishment message, Amal also provided stable income to many Shia families, unfurling a complex system of patronage across Lebanon‘s south.

After the outbreak of civil war between Lebanon‘s Christian Maronites and Muslims, Nasrallah joined Amal’s movement and fought with its militia. But as the conflict progressed, Amal adopted a staunchly unsympathetic stance towards the presence of Palestinian militias in Lebanon.

Disturbed by this stance, Nasrallah split from Amal in 1982, shortly after Israel’s invasion of Lebanon, and formed a new group with Iranian support that would later become Hezbollah. By 1985, Hezbollah had crystallised its own worldview in a founding document, which addressed the “downtrodden of Lebanon“ and named the Supreme Leader Ayatollah Khomeini of Iran as its one true leader.