Izz ad-Din al-Qassam is the man who, without knowing it, has given his name to the Izz ad-Din al-Qassam Brigades, the armed wing of the Palestinian group Hamas, and to the rocket they rain down on Israel. Born in 1882 in what is now Syria but was then part of the Ottoman Empire, he hailed from a well-off part of the Arab milieu; well off enough that he was sent by his father, a Sufi preacher, to study at Egypt's al-Azhar University, the pre-eminent seat of Islamic learning then and now. Egypt had been occupied by the British in the year of al-Qassam's birth, and so it was here that he first encountered the country that would become his nemesis, as well as the ideas that sprang up in response to their presence.

The Arab world's reaction to European dominance was given its first expression in Egypt, which was the seat of the Caliphate for six centuries, and it took many forms: some Arabs embraced liberal democracy (although not many), while others turned instead to the Islamic world's history for a guide as to how they should respond. These were the people that al-Qassam encountered at al-Azhar. Undergoing the crisis of foreign domination, they looked back to the time when Islamic civilization had been the envy of the world, and had been the one doing the dominating. The key to repeating this success, they believed, was to return to a simpler way of life which was more in accordance with the fundamental precepts of the Islamic faith; rather than embracing modernity, they would reject it entirely.

Al-Qassam became immersed in this Islamic revival movement while he was in Cairo, and he received military training in the Ottoman Army during World War I. After World War I he returned to Syria. After the war the Middle East had been parcelled out between the European powers, with Britain taking over Palestine and Syria going to the French; all this despite the fact Arab rulers, who had fought with Lawrence of Arabia against the Ottomans, thought they had been promised independence. Al-Qassam was particularly concerned by the French style of colonialism, which sought to spread secularism through its dominions. He was instrumental in an anti-French uprising in 1921 and had to flee the French sphere of influence after they sentenced him to death in absentia. His destination was the British Mandate of Palestine.

Palestine was a changing land, not only because of the British administration but also because of Jewish immigration. The British allowed a limited number of Jews to come to Palestine and settle, and many of them purchased agricultural land from absentee Arab landlords. The Arab peasants who previously worked this land were obliged to leave in such instances, and they swelled the ranks of the urban poor in places like Haifa, where al-Qassam made his new home. Disturbed by the breakdown of the traditional social compact and the complicity of the Palestinian landowning class in the process, al-Qassam preached a radical solution from his pulpit at a Haifa mosque: resistance through Islamic revival.

Al-Qassam preached a simple message. The solution to the problems befalling the Palestinian people (and the Arab world as a whole) was jihad. While westerners often translate jihad as "holy war", this is not exactly what it means, or rather does not exhaust its meaning. Jihad actually translates as "struggle", and this can be a military struggle but can also mean the individual struggle to live in accordance with religious values or the struggle to hold together a society based on Islamic values.

For al-Qassam, as for so many others who have thought in a similar vein, the word implied all of these connotations; not only a physical conflict with the British or the Jews, but a radical Islamization of Palestinian society in accordance with fundamentalist principles. This is the process one sees depicted in a different context in the 1966 film Battle of Algiers, in which the National Liberation Front first "purify" the casbah by spreading Islamic morality through intimidation and education, and only then take the battle to the French.

This was the route that al-Qassam followed in Palestine. He did not immediately attempt to organize an armed uprising. At first, he ran social programmes for the poor and became involved in the Muslim Young Men's Association, and encouraged the rural poor to set up agricultural co-operatives. He became imam at a Haifi mosque, attracting crowds of thousands for Friday prayers, and was appointed marriage registrar for his district; this allowed him to travel around the area, meeting important individuals and clans to spread his message. As with most fundamentalists, it was not the intricacy or cleverness of his message that made him popular, but rather its simplicity and ability to appeal to the disenfranchised poor.

Al-Qassam's attitude stood in stark contrast to that of the traditional religious powerbrokers in Palestine, who were headed by the British-appointed Mufti of Jerusalem. From rich backgrounds and with conservative inclinations, the traditional leaders of Palestine's Arab community seemed to be doing little to alleviate the community's travails, and at worst seemed to be helping the occupier. Al-Qassam, on the other hand, was a populist who lived a simple existence alongside his congregation, and was hence more likely to channel their frustrations and anger.

In August 1929, Palestine experienced a tumultuous few weeks of riots in which over a hundred Jews and Arabs were killed after a dispute over the Western Wall caused the Mufti to voice the long-running Palestinian complaint that the Jews planned to take over the al-Aqsa mosque, the holiest site for Muslims in Jerusalem. The violence proved to have a radicalizing effect on both Jews and Arabs, but the political situation calmed down to a relative norm soon after. To al-Qassam and his followers, this seemed unacceptable. The Mufti and the traditional establishment seemed constrained by their closeness to the British: if the Jews really planned to take over al-Aqsa, then wasn't action necessary? In 1930, al-Qassam took the hills in northern Palestine and began to wage a guerrilla and terrorist campaign against British and Jewish targets.

Al-Qassam's campaign lasted for five years before he was gunned down by the British. The Mufti of Jerusalem had declined to support his campaign or issue a fatwa in favour of it, arguing that a strategy of negotiation with the British could deliver a future for Palestinian Arabs. Al-Qassam did however manage to obtain a fatwa from the Mufti of Damascus authorizing his campaign, beginning a relationship between Palestinian radical groups and Damascus which continues to the present day; the most senior ranks of the Hamas leadership still reside in Damascus.

Despite opposition from the Mufti of Jerusalem, al-Qassam's programme of terror had a degree of support among the lower ranks of the Palestinian Arab community, and his death became a rallying point for anti-British and anti-Jewish sentiment. Further radicalization occurred. Thousands flocked to his funeral and subsequent protests, and his followers continued their attacks on Jewish and British targets. Soon, the more broadly-based revolt that al-Qassam had wanted to spark came onto the scene; this was the Arab Revolt of 1936 - 9, which was supported by all of the traditional Palestinian Arab leadership, perhaps because they felt they would be able to control it more easily now al-Qassam was off the scene, but mainly because the pressure from below had simply become too great. Palestinian Arabs were in a mood for rebellion, and the ruling class could no longer contain them.

The Arab Revolt eventually failed with the death of thousands of Arabs, and Israel was established on part of the former British mandate of Palestine. Despite this failure, Hamas choose to glorify the name of al-Qassam for many reasons. The parallels between his life and their vision of their own jihad is uncanny. They share his goals both of thouroughly transforming Palestinian society in the image of their own view of fundamentalist Islam, and of unbendingly opposing Jewish and Western influence in the land between the Jordan River and the sea.

Like him, they refuse to talk with their enemies or reach compromises like the Mufti did in the 1930s and as their Palestinian rivals, the secular Fatah, do now. Rather than becoming tainted by talks with Israel or by wealth as they view Fatah as being, Hamas see themselves as the saviours of the poor and disenfranchised, who live alongside the people and provide them with social services and express their frustrations, again as al-Qassam did. They oppose the traditional Palestinian leadership almost as strongly as they oppose Israel, if not more so, because the former is the enemy within; their ejection of Fatah from the Gaza Strip in the 2007 coup showed almost as much brutality as Hamas have practiced against Israel.

Each rocket that lands in Israel bearing the name of al-Qassam embodies at least three ideas: the first is the military struggle against Israel which Hamas will continue until it or its antagonist is destroyed; the second is the Islamic society that Hamas want to build on the ruins of Israel, and which is the force that animates them in their military struggle; and the third is their glorification of martyrdom in the vein of al-Qassam, whose own death triggered larger events and served as the greatest act of propaganda for his cause of which he was capable. It would be unwise to expect Hamas to fall out of love with any of these ideas any time soon.