As Pope Emeritus Benedict XVI returned Thursday to the Vatican, he presented the Catholic Church with the unprecedented situation of two popes living a short distance from St Peter’s Square.

Benedict, now 86, returned to the compound by helicopter, just as he left on his resignation on Feb. 28, when he moved to Castel Gandolfo, a hilltop town south of Rome where popes have summered for centuries.

Wearing the white papal cassock, he landed at the Vatican helipad and was then driven to his new home, the remodeled Mater Ecclesiae monastery on the edge of the Vatican gardens.

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“Pope Francis was there to welcome him with brotherly cordiality,” the Vatican said in a statement.

“Benedict XVI is happy to be back in the Vatican, where he will dedicate himself to the service of the church with prayer above all,” the Vatican remarked.

Ahead of his resignation, Benedict stressed that he would keep a low profile by living his final years “hidden from the world” and “withdrawn into prayer.” Most of all, he promised “unconditional reverence and obedience” to his successor. The former pope repeated his intentions on March 23 on the historic meeting with Pope Francis at Castel Gandolfo.

But despite Benedict’s efforts to dissipate concerns about potential conflicts, many observers have raised eyebrows at the unprecedented cohabitation.

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Adding to the perplexity is the fact that Benedict’s secretary, Archbishop Georg Gaenswein, will move in with the former pope at the Mater Ecclesiae monastery, while keeping his day job as prefect of Pope Francis’s household. Benedict’s second secretary, Rev. Alfred Xuereb, has also been serving Pope Francis since his election.

With two pontiffs in the Vatican — and sharing their personal aides — concerns were raised that conservative high prelates might keep Benedict as their point of reference, while opposing Francis’ announced reforms. The charismatic pope has yet to solve the Church’s dramatic problems highlighted by the Vatileaks corruption scandal.

Abdicating popes did not have favorable fates in history. Pope Celestine V, the last pope to resign willingly in 1294, was confined to a fortress by Boniface VIII and died there within a year and a half — probably killed, as a hole found in his skull suggests.

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Pope Pontian, possibly the first pope to resign in 235 A. D., was condemned to exile in salt mines in Sardinia and died of maltreatment soon after. Still others died soon after their abdication.

None lived in Rome, keeping the title of Roman pontiff emeritus or pope emeritus, the papal name and the possibility to be addressed as “his holiness.”

Benedict appeared less frail than he was when he met Pope Francis at Castel Gandolfo.

“The house is comfortable, I’ll work well here,” he said as he arrived at his new home.

Image: Benedict XVI during his farewell on Feb. 28, 2013. Credit: Rossella Lorenzi