Fred Phelps Sr., a fire-and-brimstone preacher whose anti-gay picketing at military funerals inflamed the nation and drew international scorn but was protected by the Supreme Court as an exercise in free speech, died March 19 at a hospice in Topeka, Kan. He was 84.

The Topeka-based organization Rev. Phelps founded, Westboro Baptist Church, announced the death on its Web site but did not provide the cause. The message said he had “Gone The Way of All Flesh.”

Rev. Phelps was an ordained Baptist minister, a disbarred Kansas lawyer and, according to a BBC documentary, the patriarch of the “most hated family in America.”

The Southern Poverty Law Center, a prominent civil rights group, described his Westboro congregation as a “family-based cult” and “arguably the most obnoxious and rabid hate group in America.”

The expression of Rev. Phelps’s bigotry even managed to offend the conscience of the Ku Klux Klan, which staged protests to counter Westboro’s demonstrations at military funerals.

The church’s following consisted mainly of the extended Phelps family and assorted outsiders who shared the founder’s view of an unforgiving, vengeful God poised to destroy a nation of sinners. Rev. Phelps dispatched followers to parks and street corners with anti-gay and anti-Semitic placards, some wielded by his grandchildren as young as 7.

His wrath knew few bounds, attacking in profane terms gay people, Jews, minorities, immigrants, politicians, celebrities and church leaders whose more tolerant theology he considered an abomination.

“You’re not going to get nowhere with that slop that ‘God loves you,’ ” he told the Religion News Service. “That’s a diabolical lie from hell without biblical warrant.”

The group, which has no ties to any official Baptist church body, began drawing wide attention in the 1990s for its vitriolic and relentless campaign against homosexuality. The church’s rise coincided with changing attitudes and policies toward the gay community, including President Bill Clinton’s “don’t ask, don’t tell” policy for gays in the military.

Rev. Phelps chose funerals — and eventually military funerals, in particular — as his chief forum for the denouncement of homosexuality. His slogan, “God Hates F---,” used an incendiary term for gays and was widely repeated at their public appearances and in their promotional material.

He had discerned that occasions of public grieving would draw media attention that would amplify his message. The tactic, which was roundly rebuked, won airtime on evening newscasts and tabloid-style TV talk shows.

Rev. Phelps and his followers protested at hundreds, perhaps thousands, of funerals, including those of entertainer Frank Sinatra, Sen. Barry Goldwater (R-Ariz.), civil rights activist Coretta Scott King and the miners who died in the 2006 Sago Mine disaster in West Virginia.

He also picketed the funeral of Fred Rogers, explaining that the children’s TV show host neglected to warn young viewers that sodomy is a sin.

The public outcry was particularly strong when Westboro followers picketed the 1998 funeral of Matthew Shepard, the college student who was tortured, tied to a fence and left to die near Laramie, Wyo., apparently because he was gay. Horrific in its violence, the killing sparked a national conversation about hate crimes.

In the 2000s, the Westboro group began picketing at funerals for troops who died in the wars in Iraq and Afghanistan. Rev. Phelps argued that God killed American troops to punish the country for its tolerance of gays. At memorial services, Rev. Phelps and his supporters displayed placards with messages such as “Thank God for Dead Soldiers.”

One of the protests, at the 2006 funeral of Marine Lance Cpl. Matthew A. Snyder, who died while serving in Iraq, led Snyder’s family to sue Westboro in federal court for invasion of privacy and intentional infliction of emotional distress.

A jury awarded the Snyder family nearly $11 million in damages, an amount later reduced by the judge. An appellate court, citing protected speech, ruled in favor of the church. In 2011, the Supreme Court upheld the appellate court’s decision in an 8 to 1 ruling.

“Given that Westboro’s speech was at a public place on a matter of public concern, that speech is entitled to special protection under the First Amendment,” Chief Justice John G. Roberts Jr. wrote for the majority. “Such speech cannot be restricted simply because it is upsetting or arouses contempt.”

Reacting to Westboro’s tactics, dozens of states and the federal government passed laws to create buffer areas near the sites of funerals. Rev. Phelps and his daughter, Shirley Phelps-Roper, who often acted as a church spokeswoman, were placed on a list of extremists banned from entry into the United Kingdom for “fostering hatred which might lead to inter-community violence.”

Rev. Phelps said he found comfort in being a pariah. “If I had nobody mad at me,” he once told the Wichita Eagle, “what right would I have to claim that I was preaching the gospel?”

Fred Waldron Phelps was born in Meridian, Miss., on Nov. 13, 1929. After his mother died of cancer, he was raised mostly by an aunt. His father, a detective for the Southern Railway, was often away on business.

He was ordained as a Baptist minister at 17 and bounced around as a street-corner preacher while taking classes at various colleges. His denunciations of rampant “petting” by students at John Muir College in Pasadena, Calif., were covered by Time magazine.

While evangelizing at a church in Phoenix, he met Margie Simms. They married in 1952 and two years later settled in Topeka, where shortly thereafter Rev. Phelps started the Westboro church. He sold vacuum cleaners and baby carriages during lean years and, in the early 1960s, graduated from Washburn University in Topeka and its law school.

Incongruously, he took on many civil rights cases. But his income until the mid-1970s came largely in the form of proceeds from door-to-door candy sales by his 13 children.

After a series of complaints from his legal clients, the Kansas Supreme Court disbarred Rev. Phelps in 1979, citing his “little regard for the ethics of his profession.”

In federal court, he later unsuccessfully sued Sears, Washburn University and other institutions over a variety of grievances. He also sued President Ronald Reagan for sending an ambassador to the Vatican, claiming the appointment was a violation of religious freedom under the First Amendment.

In 1989, after prolonged legal woes, he surrendered his license to practice law in federal courts. He soon made a foray into politics, running high-venom and unsuccessful campaigns throughout the 1990s as a Democratic candidate for Kansas governor and U.S. senator. (He received 30 percent of the primary vote in his 1992 Senate bid.)

Rev. Phelps said he first began anti-gay demonstrations in 1991 after one of his grandsons was propositioned at Topeka’s Gage Park, which he called a gay cruising spot. He called for a “decency drive” and sent such a barrage of faxes to city officials that the state moved to prohibit harassment by fax.

A complete list of survivors was not immediately available. Rev. Phelps was estranged from at least four of his children, including sons Mark and Nathan, who alleged years of physical abuse by their father and who left his church years ago. (Nathan recently said that his father had been expelled by the church in 2013, but a church spokesman declined to address the matter with news media outlets.)

Two of Rev. Phelps’s granddaughters who participated in protests left the church last year and apologized for the public pain they caused. Their grandfather, however, had never intended the message to be gentle.

“Hate,” his bumper stickers proclaimed, “Is a Bible Value.”