ROME — Just when you think you have Pope Francis figured out, he surprises you. In that spirit, Monday’s appointment of Cardinal Robert Sarah of Guinea as the new head of the Vatican’s department for liturgical policy will certainly surprise some.

Sarah becomes the second African to have the Vatican’s top liturgical post, after Nigerian Cardinal Francis Arinze from 2002 to 2008.

When he recently removed US Cardinal Raymond Burke from a senior Vatican job, many observers concluded that Francis simply didn’t want such a strong conservative on his team. Yet he’s now handed over the Congregation for Divine Worship and the Discipline of the Sacraments to an equally strong conservative in the 69-year-old Sarah, who since 2010 has led a Vatican office called Cor Unum that oversees Catholic charities.

Sarah was part of the conservative opposition at the recent Synod of Bishops on the family to an interim report that contained daringly positive language on same-sex unions and other relationships that fall outside the bounds of Catholic teaching on marriage.

A former Archbishop of Conakry in Guinea, Sarah was also part of the African contingent at the synod that objected when no prelate from the continent was named to the drafting committee for the final document, leading Francis to add Cardinal Wilfrid Fox Napier of South Africa to the body.

In other words, this isn’t exactly the profile that perceptions of Francis as a “liberal pope” would lead one to expect in his choices for key jobs.

Once rumored as a possible papal candidate himself, Sarah brings an impressive pedigree to his new position.

He was born in 1945 in what was then known as French Guinea, and entered the seminary in Ivory Coast. He returned in 1960 to continue his studies at home, but after a year, the Marxist-inspired Democratic Party of Guinea nationalized all Catholic schools, including the seminary, and Sarah and his fellow candidates for the priesthood had to regroup. He eventually finished his undergraduate studies in Senegal, then headed for Rome to the Gregorian, followed by a stint at the Studium Biblicum Franciscanum in Jerusalem.

After just 10 years as a priest, Sarah was named the archbishop of Conakry in 1979, when he was barely 34 years old.

In 1985, Sarah was elected president of the bishops’ conference of Guinea, and became the primary interlocutor with the government in the chaotic period after the death of the Marxist dictator Ahmed Sékou Touré in 1984.

Sarah became an outspoken critic of authoritarian and corrupt regimes. When Pope John Paul II visited Guinea in 1992, Sarah publicly asked the pope to push African leaders to clean up their act.

“Tell the African governments that reforms will be meaningless if they are tainted in blood, provoking considerable human and economic catastrophes,” he told the pope.

When the ruling regime in Guinea tossed opposition leader Alpha Conde into jail in 1999 after a disputed election, Sarah publicly demanded his release.

While still in Conakry, Sarah was also elected president of the Episcopal Conference of West Africa, another sign that his fellow bishops saw him as a leader.

In October 2001, Sarah was called to Rome to become the secretary, or No. 2 official, at the powerful Congregation for the Evangelization of Peoples (better known as “Propaganda Fidei”). In that role, he became seen as a go-to figure inside the Vatican for bishops from all over the developing world.

Nine years later, Sarah was tapped to take over at Cor Unum from German Cardinal Paul Cordes, symbolically expressing a transition in leadership of the Church’s charitable enterprise from the first world to the developing world.

On what Americans know as the “culture wars,” meaning debates over abortion, gays and lesbians, and the family, there’s no doubt Sarah profiles as a staunch conservative.

During the 2009 Synod for Africa, he condemned a Western “theory of gender” which he said is trying to push Africa “to write laws favorable to … contraceptive and abortion services (the concept of ‘reproductive health’) as well as homosexuality.” All this, Sarah said, “is contrary to African culture and to the human truths illuminated by the divine Revelation in Jesus Christ.” Africa, he said, “must protect itself from the contamination of intellectual cynicism in the West.”

He revived many of those arguments at the recent Synod of Bishops on the family.

In May 2012, the Vatican issued new rules for the Rome-based federation of Catholic Charities, Caritas Internationalis, which stipulated that Cor Unum will monitor the group’s Catholic identity, that it must approve any cooperative agreement between Caritas and other non-governmental organizations (NGOs), and that top officials of Caritas must swear loyalty oaths before Cor Unum’s president.

In December 2012, the Vatican released another set of rules for Catholic charities generally, also aimed at beefing up Catholic identity and ties to the hierarchy. In signing the document, Benedict XVI wrote that he did so upon Sarah’s recommendation. Among other things, the rules state that a Catholic charity may not take money “from groups or institutions that pursue ends contrary to the Church’s teaching.”

At the time, a European veteran of Catholic charities familiar with the drafting process for the new rules said that Sarah played a leading role. The concern over taking money, he said, reflected Sarah’s African experience. During the 1980s and 1990s, this observer said, Sarah became concerned that United Nations agencies and major NGOs were using their money and influence to undercut traditional African values.

So what does the appointment of Sarah tell us about Pope Francis?

First, that despite the removal of Burke, he doesn’t seem to be conducting an ideological purge in senior Vatican positions, nor does he appear to be doling out punishment to those who opposed the progressive line at the recent synod.

Second, Francis knows that many African prelates felt compelled to assert themselves during the synod, and wanted to send a signal of respect for the continent by making sure there’s an African prefect of a major Vatican department.

Third, the Sarah appointment may also be part of a political balancing act by Francis. The pontiff may be trying to “reach across the aisle,” to use the American argot, and assure conservatives that he’s not the enemy.

Doing so in the realm of liturgy may be especially deft, since the Church’s liturgical purists have felt some of the deepest ambivalence about Francis. They tend to believe he’s not nearly as passionate about the Church’s liturgical traditions as Benedict, and his crackdown on a small religious order called the Franciscan Friars of the Immaculate that celebrates the old Latin Mass has exacerbated those impressions.

In that light, handing responsibility for liturgy over to someone traditionalists generally perceive as a friend may shift the terms of debate.

Francis said at the end of the recent synod that he wants the Church to steer a middle course between “hostile inflexibility” and “destructive do-goodism,” which is another way of saying he doesn’t want to veer toward one ideological extreme or another.

Some on the Catholic right may have had an especially hard time believing that, but perhaps with the surprising choice of Sarah as the pope’s liturgy czar, it will seem a bit more credible.