In recent speeches, tweets and remarks, Francis has called for a negotiated settlement in Syria but has also condemned the use of chemical weapons.
"War never again! Never again war!" he tweeted earlier this week.
It's an anti-war exhortation that echoes those issued by popes past starting with Pope Pius XII in his 1951 Christmas radio message. Pope Paul VI uttered the same words at the United Nations in 1965 as the Vietnam War raged. Pope John Paul II repeated them in calls for peace in Bosnia and Iraq and Benedict XVI used the refrain during a 2011 peace meeting with religious leaders in the Umbrian hilltop town of Assisi.
John Paul took his anti-war initiative a step further when, on the eve of the 2003 U.S.-led invasion of Iraq, he sent a personal envoy to U.S. President George W. Bush to try to dissuade him from starting war.
For Francis, whose namesake St. Francis of Assisi was known for his message of peace, Saturday's public vigil will be something of a test to see if his immense popular appeal translates into solid popular support for his anti-war initiative.
On Wednesday he urged Romans in particular to come to St. Peter's for the vigil, which will feature moments of silent prayer as well as remarks by Francis.
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