Omar Abdel Rahman in 1993. The Egyptian-born “blind sheikh” and spiritual leader who was convicted in 1995 of being a mastermind of terrorist plots against the United States died Feb. 18 at a federal prison in Butner, N.C. (Said Elatab/Associated Press)

Omar Abdel Rahman, the Egyptian-born “blind sheikh” and spiritual leader who was convicted in 1995 of being a mastermind of terrorist plots against the United States, and who was called the “godfather” of radical Islamist movements, died Feb. 18 at a federal prison in Butner, N.C., where he was serving a life sentence. He was 78.

Kenneth McKoy, a Bureau of Prisons official, confirmed the death to the Associated Press. The cause was diabetes and heart disease.

Abdel Rahman, who was blind from an early age, had denounced secular tendencies in other Muslims since the 1960s and was linked for decades with extremist Islamist circles in Egypt and abroad. He was twice acquitted of helping plot the 1981 assassination of Egyptian President Anwar Sadat — whom he denounced as “not a Muslim” — and built an alliance with al-Qaeda leader Osama bin Laden while living in Afghanistan in the 1980s.

After moving to the United States in 1990, Abdel Rahman preached at storefront mosques in Brooklyn and New Jersey, and came under federal scrutiny after a 1993 bombing at the World Trade Center left six people dead and more than 1,000 injured.

Several of his followers were convicted in the bombing, although Abdel Rahman was not. Instead, he was arrested on broader conspiracy charges of planning to “levy a war of urban terrorism against the United States.”

Abdel Rahman in 1989, at a court appearance in Egypt. (Mike Nelson/AFP/Getty Images)

Among other actions, Abdel Rahman was accused of plotting a “day of terror” in which simultaneous bombs would blow up the United Nations, the Lincoln and Holland tunnels in New York City, the George Washington Bridge and the building housing New York’s FBI headquarters.

“All I know is that I have nothing to do with this case other than that I am a cleric who prayed in a mosque,” Abdel Rahman said during his 1995 trial in federal court in New York. “I did not speak. I did not give orders. I have nothing to do with anything.”

Even while he being held for trial, Abdel Rahman delivered long sermons from jail, with his telephone messages amplified by microphones in the mosques frequented by his followers.

During the eight-week trial, Abdel Rahman’s high-powered defense team included celebrity lawyers William Kunstler and onetime U.S. attorney general Ramsey Clark. The evidence included secretly recorded wiretaps, which prosecutors said indicated Abdel Rahman’s intent to wage a holy war in the United States.

In the end, he and nine followers were found guilty. At his sentencing, Abdel Rahman spoke in Arabic for almost 90 minutes, touching on such subjects as birth control, homosexuality, former Egyptian president Gamal Abdel Nasser and his U.S. green-card status.

“This is an infidel country,” Abdel Rahman said in his rambling speech. “It has an infidel White House. It has an infidel Congress. It has an infidel Pentagon. And this is an infidel courthouse.”

He was sentenced to life in prison.

Abdel Rahman in 1988. (Mike Nelson/AFP/Getty Images)

He was held virtually incommunicado at several federal facilities and allowed only one 15-minute phone call with his family every week to 10 days. Two of his sons, who had been associated with bin Laden and al-Qaeda, were not permitted to visit.

Nonetheless, Abdel Rahman became a powerful symbol in certain quarters of the Muslim world. Al-Qaeda leader Ayman al-Zawahiri called on Egyptians to kidnap Americans in effort to win Abdel Rahman’s release. Zawahiri’s younger brother proclaimed Abdel Rahman “the godfather of all Islamic movements.”

After the terrorist attacks on the United States on Sept. 11, 2001, Peter Bergen, a journalist and biographer of bin Laden, described Abdel Rahman as the “spiritual guide of 9/11.”

Omar Abdel Rahman was born May 3, 1938, in El Gamalia, Egypt. He lost his eyesight before his first birthday as a result of illness.

He studied a Braille version of the Koran and had memorized it by age 11. In 1965, he received a doctorate in Islamic law from Cairo’s al-Azhar University, the world’s oldest Islamic university.

He preached at a small mosque in rural Egypt and became known for his criticism of the secular leadership of Nasser, calling him “the wicked pharaoh.”

After being jailed for several months for his comments, Abdel Rahman spent three years teaching in Saudi Arabia, where he became more deeply immersed in a militant, hard-line form of Islam. Back in Egypt in the late 1970s, he was seen as the spiritual leader of al-Gama al-Islamiyya, a radical group later tied to terrorist activities.

Abdel Rahman became an outspoken opponent of Sadat, whose overtures to Israel, culminating in the 1979 Camp David Accords, were seen as anathema to conservative Muslims. The Egyptian president was killed by assassins on Oct. 6, 1981.

Although he denounced Sadat as an infidel, Abdel Rahman was acquitted of any role in the assassination plot. He later fled to Afghanistan, where he was closely allied with bin-Laden’s growing al-Qaeda movement.

From 1985 to 1990, Abdel Rahman traveled widely throughout Europe, Africa, Asia and the United States, speaking to Muslim audiences. He spent a considerable amount of time in Peshawar, Pakistan, a hotbed of radical Islamist sentiment.

By 1990, Abdel Rahman had returned to Egypt, where he was under close watch by authorities and barred from leaving the country. He managed to escape, according to one account, by being smuggled out in a washing machine.

Despite being on anti-terrorism watch lists, he traveled to Sudan, where he received a visa to enter the United States. After his arrival in New Jersey, he obtained a green card for residency. When it was revoked in 1992, he asked for political asylum.

Abdel Rahman had two wives and 10 children; a complete list of survivors could not be confirmed. One of his sons, Ahmed Abdel Rahman, was killed by a U.S. drone strike in Afghanistan in 2011.

In 2005, one of his lawyers, Lynne Stewart, was convicted of providing material aid to a terrorist organization for smuggling messages from Abdel Rahman to the al-Gama al-Islamiyya organization. After first receiving a 28-month prison sentence, which she began to serve in 2009, she was resentenced in 2010 — to 10 years — but was released in 2013 for health reasons.

In 2012, Egypt’s president, Mohamed Morsi, called for Abdel Rahman to be transferred to Egypt for “humanitarian reasons” as part of a prisoner exchange with the United States.

The request was denied.