For the first time in modern history, a sitting pope will preside over his predecessor's funeral next week, with Pope Francis leading a "simple" ceremony for Benedict XVI.

Benedict, the first German-born Pope in 500 years, died on Saturday at the age of 95 in the Vatican. His successor, Pope Francis, had previously warned that the ex-pope was "very ill".

The first pontiff to resign since the Middle Ages due to declining health, Benedict renounced the papal throne in 2013 -- but lived within the Vatican and still wore white.

Vatican Spokesperson Matteo Bruni told journalists at a briefing after Benedict's death that the 95-year-old would have a "solemn but simple" funeral on Thursday.

The death of a pope traditionally creates a power vacuum at the top of the church. However, no such vacuum exists in this case, as Francis is in charge. Unlike when previous popes have died, there is no need to call a conclave to elect a new pontiff.

Under rules set out in 1996, a pope must be buried between four and six days after his death. The process of his burial is usually decided by cardinals who gather from around the world and organize the Vatican's nine days of mourning, known as novemdiales.

Earlier, German Chancellor Olaf Scholz said the world has lost a "formative figure" of the Catholic Church with Benedict's death.

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