ROME – Shortly after Ghanian Cardinal Peter Turkson was seen smiling as he shook hands with Pope Francis during the pontiff’s annual Christmas speech to members of the Roman Curia, the Vatican announced that he was out of his job.

After rumors began to circulate last week, Turkson confirmed via Twitter on Sunday that he had submitted his letter of resignation to Pope Francis, telling journalists Tuesday that it was simply a matter of his 5-year term coming to an end.

In their Dec. 23 noontime bulletin, the Vatican announced Pope Francis’s decision to accept Turkson’s resignation, citing the end of the term limit and a formal evaluation of the department over the summer as the primary reasons.

In their statement, the Vatican noted that “In August 2016, Pope Francis announced the creation of the Dicastery for Promoting Integral Human Development as a result of the merger of four pre-existing pontifical councils. The new dicastery began to operate in January 2017.”

“At the end of the first five years of activity with statutes ad experimentum and following the results of the evaluation visitation carried out this past summer, the superiors of the Dicastery for Integral Human Development placed their mandates in the hands of the Holy Father,” the statement said.

Thanking Turkson and other leaders of the department for their service, the Vatican announced the pope’s decision to name current department undersecretary Canadian Jesuit Cardinal Michael Czerny as the interim prefect beginning January 1, 2022. Italian Sister Alessandra Smerilli will continue in her role as secretary, but also on an interim basis.

Turkson was appointed head of the former department for Justice and Peace in 2009, meaning he has been leading a Vatican department for nearly 13 years.

His exit from the department has come as a surprise to many for several reasons, the first of which is that he is only 73, just two years shy of the mandatory retirement age for cardinals and bishops.

From the beginning of Francis’s papacy in 2013, Turkson has been considered one of the pope’s key allies, and has played a crucial role in implementing the pope’s social and political agenda.

Many observers believe Turkson’s unexpected exit is related to internal tensions in his department, which merged four difference offices into one-mega structure.

Others point to the inherent tensions with his relationship with Czerny, who Francis put in charge over the migrants and refugees section of the department, which the pontiff had reserved to his own competence, despite being officially part of Turkson’s dicastery. Czerny was named a cardinal in 2019, and it is unprecedented that a cardinal would serve under another cardinal in a Vatican department.

According to the Vatican statement, Turkson’s resignation is also the result of a formal audit of the department carried out this this past summer which was requested by Pope Francis and conducted by Cardinal Blase Cupich of Chicago.

Following that inquiry, two high-profile personalities in the department also made their exits: French Father Bruno-Marie Duffé, formerly the department’s secretary, or number two official, and Father Augusto Zampini, an Argentine who’d been named Adjunct Secretary in 2020.

Turkson met with Pope Francis on Monday and presided over a press conference Tuesday for the presentation of Pope Francis’s message for the 2022 World Day of Peace, which is observed on January 1, which was likely his last public appointment as head of his department.

Follow Elise Ann Allen on Twitter: @eliseannallen