Archbishop Oscar Arnulfo Romero, who was gunned down while celebrating Mass is being made a saint.In 1980, a day after urging El Salvador’s military to halt a string of abuses that would inflame a 12-year civil war in the impoverished country, Salvadoran Archbishop Oscar Romero was shot dead while celebrating Mass.

His homilies had blasted the US-backed military dictatorship while voicing solidarity with the poor, making him a Latin American human rights icon.

On Sunday at the Vatican, he will become a Catholic saint.

Romero was considered for canonisation decades ago, but his nomination stalled on concerns that he was overly political.

His reputation rebounded in 2015, when Pope Francis, a fellow Latin American committed to defending the poor, declared him a martyr who had been killed for hatred of the faith.

Romero critiqued the military government and armed leftist groups alike. That earned him animosity from both sides ahead of a civil war that lasted until 1992, leaving some 75,000 people dead and sending thousands of Salvadorans fleeing to the United States.

In 1980, at a church altar, he found a bomb meant to take his life.

“Persecution is necessary in the Church. Do you know why? Because the truth is always persecuted,” he said at the time.

Two weeks later, undeterred by death threats, the man distinguished by his bushy eyebrows and thick glasses spoke directly to soldiers.

“I beg you, I beseech you, I order you in the name of God: stop the repression,” he said.

The following day, a sniper killed the 62-year-old as he delivered Mass at a hospital chapel in the capital. The main suspect is a former soldier.

Romero’s murder was one of the most shocking of the long conflict between a series of US-backed governments and leftist rebels in which right-wing and military death squads killed thousands.

Romero was born in 1917 in a small coffee-growing town in Honduras, the second of eight brothers. As a boy, he apprenticed as a carpenter before entering the seminary and studying theology in Rome.

In 1943, he returned to El Salvador as a parish priest until becoming Archbishop of San Salvador in 1977. The military’s killing, kidnapping and arrests of priests who supported workers’ rights turned him into a staunch critic of the regime.

The Vatican said the miracle cementing his sainthood was the 2015 survival of Cecilia Flores, whose husband prayed to Romero when she was close to death in pregnancy.

“Doctors told my husband … only a miracle will save your wife,” Flores said. After her husband began praying, she instantly recovered and gave birth to a healthy son.