Romero was killed by right-wing death squad in El Salvador. Paul VI guided the church through tumult of the 1960s.

Pope Francis has made saints of two of the most contentious Roman Catholic figures of the 20th century: assassinated Salvadoran Archbishop Oscar Romero and Pope Paul VI, who reigned over one of the Church’s most turbulent eras and enshrined its opposition to contraception.

In a ceremony on Sunday before tens of thousands of people in St Peter’s Square, Francis declared the two men saints, along with five other lesser-known people who were born in Italy, Germany and Spain in the 18th and 19th centuries.

Both Romero, who was shot by a right-wing death squad while saying Mass in 1980, and Paul, who guided the Church through the conclusion of the modernising 1962-65 Second Vatican Council, were contested figures within and without the Church.

Both were naturally timid men who were thrust to the forefront of history by the convulsive political and social changes of the 20th century and both had a lasting influence on the current pontiff, Francis, Latin America’s first pope.

Romero, who had often denounced repression and poverty in his homilies, was shot dead on March 24, 1980, in a hospital chapel in San Salvador, the capital of the impoverished Central American country of El Salvador.

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

It was widely believed to have been ordered by Roberto D’Aubuisson, an army major and founder of the right-wing ARENA party.

Third pope canonised by Francis

Paul VI, a shy man described by biographers as a sometimes indecisive and tormented Hamlet-type figure, guided the Church through the conclusion of the Second Vatican Council, which had started under his predecessor, and the implementation of its reforms. He was elected in 1963 and died in 1978.

Francis often quotes Paul, showing that he is committed to the reforms of the Council, which allowed the Mass to be said in local languages instead of Latin, declared respect for other religions, and launched a landmark reconciliation with Jews.

Salvadoran Archbishop Oscar Romero was a champion of the poor [Leif Skoogfors/Corbis via Getty Images]

Still today, ultra-conservatives in the Church do not recognise the Council’s teachings and blame Paul for starting what they see as a decline in tradition.

Paul reigned in the 1960s, when many men left the priesthood and vocations fell sharply in a turbulent era of social change that coincided with the sexual revolution and the widespread availability of the birth control pill.

Despite his many reforms, Paul is perhaps best known for his 1968 encyclical “Humane Vitae” (On Human Life), which enshrined the Church’s ban on artificial birth control, saying nothing should block the possible transmission of human life.

The ban, which Paul issued against the advice of a papal commission, became the most contested Church ruling of the 20th century and is still widely disregarded by Catholics.

Paul also became the first pope in modern times to travel outside Italy to see faithful, ushering in a practice which has become synonymous with the papacy.

Paul is the third pope that Francis has made a saint since his election in 2013. The others are John XXIII, who died in 1963, and John Paul, who died in 2005.