VATICAN CITY — Pope Benedict XVI will be known as “emeritus pope” in his retirement and will continue to wear a white cassock, the Vatican announced today, again fueling concerns about potential conflicts arising from having both a reigning and a retired pope.

The pope’s title and what he would wear have been a major source of speculation ever since Benedict stunned the world and announced he would resign on Thursday, the first pontiff to do so in 600 years.

The Vatican spokesman, the Rev. Federico Lombardi, said Benedict himself had made the decision in consultation with others, settling on “Your Holiness Benedict XVI” and either emeritus pope or emeritus Roman pontiff.

Lombardi said he didn’t know why Benedict had decided to drop his other main title: bishop of Rome.

In the two weeks since Benedict’s resignation announcement, Vatican officials had suggested that Benedict would likely resume wearing the traditional black garb of a cleric and would use the title “emeritus bishop of Rome” so as to not create confusion with the future pope.

Benedict’s decision to call himself emeritus pope and to keep wearing white is sure to fan concern voiced privately by some cardinals about the awkward reality of having two popes, both living within the Vatican walls.