The founder of Israel’s Islamic Movement, Sheikh Abdullah Nimr Darwish, died on Sunday at the age of 69 at Hasharon Hospital in Petah Tikva, the movement said in a Facebook post.

Darwish suffered from a number of illnesses, according to reports, but it was not immediately clear what he died of.

Darwish founded the movement in 1971 in his hometown of Kafr Qassem, based on the ideology of the Muslim Brotherhood, and calling for an Arab-Muslim state in all of historic Palestine.

While he initially supported violence, he later shifted to a more pragmatic leadership style and supported nonviolent and democratic means to spread Islamist thought.

According to a Brookings report on the Islamist Movement, Darwish was originally a communist activist before studying Islam in Nablus from 1968 to 1971.

The founder of Israel's Islamic Movement Sheikh Abdullah Nimr Darwish seen in Jerusalem on December Thursday 19. 2006. (Olivier Fitoussi/Flash90)

The founder of Israel’s Islamic Movement Sheikh Abdullah Nimr Darwish seen in Jerusalem on December Thursday 19. 2006. (Olivier Fitoussi/Flash90)

In 1979, Darwish helped launch the “Families of Jihad” (Osrat al-Jihad), a terrorist group that sought to achieve the Islamic Movement’s goals through violent means.

While the group was behind a number of assaults — mostly damaging property — it never carried out a lethal terrorist attack. It did, however, kill an alleged Arab-Israeli “collaborator” with the Israeli security services.

In 1981 Darwish was arrested for his membership in the terror group; he was released in 1983.

While in prison, he reportedly came to the decision that he must “work in the State of Israel by Islamic values without breaking the law.”

Throughout the 1980s Darwish’s movement grew in popularity, and by 1989 it had five mayoralties and 45 seats on 11 municipal and local councils.

The group provides services often lacking in Israel’s Arab communities, including kindergartens, colleges, health clinics, mosques and even a sports league.

One of the rising stars of the movement in the 1980s was Raed Salah — a longtime pupil of Darwish — who won the mayoral election in Umm al-Fahm, the second-largest Arab-Israeli city.

Israeli-Arab Sheikh Raed Salah the leader of the radical northern wing of the Islamic Movement in Israel, prayers with supporters in Umm al-Fahm after he was released from prison on January 17, 2017. (AFP Photo/Ahmad Gharabli)

Israeli-Arab Sheikh Raed Salah, the leader of the radical northern wing of the Islamic Movement in Israel, prays with supporters in Umm al-Fahm after he was released from prison on January 17, 2017. (AFP Photo/Ahmad Gharabli)

The Oslo peace process of the 1990s proved to be a dividing moment between Darwish and more radical elements of the movement led by Salah. Darwish supported the peace process, while Salah opposed it.

This difference led to a split in the movement between the Southern Branch, which was led by Darwish, and the Northern Branch, led by Salah.

Today, the Southern Branch is represented in the Knesset as a party in the Joint (Arab) List faction. Three of the Joint List’s 13 current Knesset members are part of the movement.

The Northern Branch of the Islamic Movement was outlawed in November 2015. The government charged the group with links to terrorist groups and inciting a wave of violence.

Salah was released from prison in January after serving a nine-month sentence for incitement to violence and racism.