Choosing a name is the first significant act in office for the new pontiff and can offer pointers to the kind of leadership he aspires to.
Pope Benedict XV was considered a champion of peace
In choosing Benedict - which means "blessed" in Latin - Joseph Ratzinger told cardinals at the conclave that it was a homage to the last Benedict whose pontificate covered World War I.
Italian-born Benedict XV is best remembered for his diplomatic efforts to end the conflict and his adroit leadership during a difficult period.
He strove to remain neutral throughout his papacy, between 1914 to 1922, at a time when Catholic countries were fighting a war on opposite sides.
He protested against the use of weapons such as poison gas and drafted a plan to end the war, some of which was included in US President Woodrow Wilson's 14 Points peace deal in January 1918.
Another papal namesake, Benedict XIII (1724-30), was a Dominican monk who lived as a friar even after his election. He was more frugal than his predecessors and continued to visit the sick and the dying while in office.
Pope Benedicts who had less happy tenures in office include:
Benedict VI (972-974), whose tenure came to an abrupt end when he was strangled by a priest after the Roman citizens rebelled against him
Benedict IX (1032-1045), who appears to have assumed the papacy at the age of 12. Notoriously corrupt, he was eventually excommunicated
Benedict XI (1303-1304), whose pontificate ended suddenly when he died of suspected poisoning in Perugia, reportedly on the orders of William of Nogaret. He was beatified in 1773
Monsignor Roderick Strange, of Rome's Bader College, told the BBC he thought that Cardinal Ratzinger's choice of name was important in the light of Germany's wartime past.
Benedicts have periodically ruled the Church since the 6th Century
"He is a German... To take the name of a man who was so strenuously a champion of peace, I think is highly significant," he said.
The last Benedict was also considered to be a good administrator and, like the late John Paul II, a unifier of peoples.
He strove to reach out to Muslims and establish closer ties with Orthodox Churches which are issues which remain topical for his successor.
Turkey built a statue to Benedict XV in Istanbul as a tribute to a "benefactor of all people, regardless of nation or creed".
With his choice of name, Cardinal Ratzinger may also have been thinking of St Benedict of Norcia, a 6th Century monk who was the founder of Western monasticism and is the patron saint of Europe.
The fact that the feast day of an 18th Century St Benedict, 16 April, is also Cardinal Ratzinger's birthday may simply be a happy coincidence.
Benedict is one of a number of papal names of holy origin such as Clement, Innocent, and Pius.
John is the most popular, with 23 pontiffs taking that name. Two, John Paul I and John Paul II, used it in a double name.
There have been 16 Gregories and, as of Tuesday, 16 Benedicts.