As long as there have been popes, they have needed transportation. Footmen used to shoulder his holiness on portable thrones, known as sedia gestatoria, to greet the public during special occasions and processionals.
But human power was eventually traded for horsepower, and papal movers evolved with the times.
"Popemobile" is not an official term, but it came into vogue in the 1970s with the creation of a series of white all-terrain vehicles with bubble tops.
Through the years, dozens of vehicles have been specially tailored by carmakers like Cadillac, Mercedes and Jeep for the needs of the pontiff.
Created for Pope Leo XII in 1826, the lavish wooden carriage was adorned with the eagle crest of his papacy. The eight golden plumes atop of the Berlin signaled that it was a part of the papal fleet. It featured other intricate iconography, including the Scales of Justice and a patriarchal cross for the Catholic faith.
The carriage's interior was lined with red velvet upholstery. The interior roof included a dove, representing the Holy Spirit, which was stitched with silver thread and surrounded by golden rays.
In 1841, Pope Gregory XVI removed the seat that the coachmen had sat on and installed two large winged cherubs. The coachmen steered the carriage on horseback.
The carriage was paraded on a few celebratory and solemn occasions. Its last appearance came in September 1870, when Pope Pius IX traveled to the Basilica of Santa Maria del Popolo, days before the Papal States were dissolved as part of the unification of Italy.
To celebrate the agreement between Italy and the Holy See that recognized Vatican City as an independent state, Pope Pius XI was driven out of the Vatican in a Graham-Paige donated by the brothers who founded the Detroit-based automobile company.
In 1943, Pope Pius XII was driven back to the Vatican in the vehicle after comforting residents in a Rome neighborhood bombed by the Americans. (His Mercedes 230 had broken down during the trip.)
The car's service in the papal fleet extended from 1928 to 1958, according to Sandro Barbagallo, curator of the Vatican Museum's division for historic collections.
The Lictoria Sex, as it was known, was presented to Pius XI in June 1930 by about 200 workers and designers who had built the burgundy and gold Italian car. It was given to him during a wave of automotive generosity by other companies, including Graham-Paige, that also wanted to offer gifts to celebrate the pontiff's 50th anniversary in the priesthood and the agreement between Italy and the Vatican.
The interior, which was designed to emulate a Venetian-style drawing room from the 1700s, was also covered in a canopy embroidered with a large dove. The throne was a crimson brocade. And the panels of inlaid wood were built to store objects like the breviary.
It was used by Pius XI, but Pius XII preferred to use the more understated Graham-Paige during World War II.
Pope Pius XI is said to have called this two-and-half ton black livery “a wonder of modern technology” during a test drive in the Vatican Gardens.
The chassis and the eight-cylinder, 80-horsepower engine, which give the vehicle a top speed of about 62 m.p.h., were only slightly modified. But the interior was outfitted with a single seat covered in silk brocade, and the roof lining was embroidered with a dove.
It featured tinted safety glass and a control panel through which the pope could direct the driver with the press of a button.
The 1930 vehicle, designed by Ferdinand Porsche, would be the first of about a dozen gifts from Daimler-Benz, and was retired after about 25,000 miles on the road. It is currently on display at the Vatican Museum.
The Mercedes 300D, with whitewall tires and a dark finish, was extensively modified for Pope John XXIII.
It is believed to be the first vehicle in the papal fleet with a convertible top and a rising throne rear seat, which was flanked by controls for air-conditioning and a two-way radio.
The Stuttgart manufacturer also modified the running boards and extended the wheelbase about 18 inches, and attached the pope's coat of arms to the side.
John Paul II used this vehicle throughout his papacy, according to Dr. Barbagallo. It had a six-cylinder, 170 horsepower engine. The convertible top was designed specially for the Vatican.
Fiat presented this vehicle to Pope John Paul II in 1980 during a visit to Turin, Italy. It marked the beginning of the white all-terrain vehicles that have come to be associated with the popemobile-style vehicles of today.
The 1980 Fiat 1107-Nuova Campagnola served as the popemobile for a year, until John Paul was shot in it while greeting throngs of people in St. Peter's Square on May 13, 1981.
A Lincoln Continental was first customized for Pope Paul VI's trip to New York City in 1965 with a clear folding top and a thronelike seat in the back that could be cranked higher for better visibility.
It and later models were modified by the coach-building company Lehmann-Peterson, which outfitted limousines with security features like metal armor and bulletproof glass for presidents, dignitaries and rock stars.
This giant white and yellow bus was made for John Paul II’s visit to Ireland, when he became the first pontiff to set foot in the country.
The 15-seat vehicle was later acquired by the National Wax Museum in Dublin, and until recently, it was available for city tours and for rent for bachelor and bachelorette parties at $385 an hour.
The white boxy truck with gold and brass trim was among the first in the fleet to resemble the popemobiles as they are known today.
The 230 G was equipped with a large removable plastic cupola on the back for John Paul II's trip to Germany in 1980. Instead of a thronelike chair, the pope had a white leather bench. He could also stand.
A climate control system prevented fogging and overheating during long processional drives, and recessed lighting inside the vehicle helped spectators get a better view of the pope. After the assassination attempt on John Paul II in 1981, the bodywork was finished with bulletproof glazing.
Several iterations of the vehicle, all painted in "mystic white finish," would carry subsequent pontiffs, including Benedict XVI. It inspired the designs of the M-Class, which had a similar body and a rounded cupola.
General Motors spent $600,000 and about six weeks to produce this car in papal white for John Paul II’s visit to Mexico City, where he addressed a stadium full of more than 100,000 people.
Workers adjusted the roof and the rear door on the driver's side, adding a set of folding stairs for easier access. A white leather platform chair, which was stitched with the papal seal, could be raised about a foot with a one-horsepower compressor in the trunk of the car.
The vehicle had a U-shaped handrail in front of the chair that the pontiff could hold on to if he wanted to stand.
The pope blessed the car, but because of security concerns, he never used it. The Petersen Automotive Museum in Los Angeles acquired it at an auction in 2009 for $57,200.
Father Renzo Zocca, a parish priest from Verona, Italy, gave his four-speed 1984 Renault with 186,000 miles to Pope Francis in September 2013. Francis reportedly planned drive it himself on short trips around the Vatican.
While in the United States, Francis will be driven in a modified Jeep Wrangler similar to the one he used during his South American trip this summer, according to the Vatican.
There will be several available for each leg of his journey, and backups in case of a breakdown. They were shipped in August and are now in the possession of the Secret Service.
To the chagrin of security personnel, Francis prefers to communicate with the people without a bulletproof barrier, which he described as being inside a “sardine can.”
“It’s true that anything could happen,” he told a Barcelona newspaper. “But let’s face it, at my age I don’t have much to lose.”