Vatican Letter: The world's smallest army is celebrating its fifth centenary in the world's smallest state. The Vatican City is the tiniest sovereign state in the world, and the celebrations marking the 500th anniversary of the Vatican's official army, the Swiss Guards, reach their climax on January 22nd - on that evening in 1506, a group of 150 Swiss soldiers entered the Vatican for the first time and were blessed by Pope Julius II.
The imposing size of St Peter's and the lengthy history of the Papal power make it difficult to grasp that the Vatican has been a sovereign state for less than 80 years and that it is such a tiny independent entity.
Apart from his role as head of the Catholic Church and Bishop of Rome, the Pope is also head of state in the Vatican City.
It is a state with its own sovereign government, governor, legislature and judiciary, its own police force and its own army in the form of the Swiss Guards.
It has its own radio station, daily newspaper, heliport, train station, filling station and duty-free shops, post office and stamps, diplomatic corps, internet domain (.va), and a resident population of over 920 people, including some Vatican staff and the 100 members of the Swiss Guards.
The Vatican State even has its own coins and banknotes. Despite popular jokes, they are not known as Peter's Pence, and Vatican-issued euro coins and notes are quickly snapped up as collectors' items.
The three Lateran treaties signed with Italy in 1929 acknowledged the full sovereignty of the Vatican State, restored some of the temporal powers of the papacy and established the territorial extent of the new state, which is totally landlocked within the City of Rome by a land border of 3.2 km. With a land area of 0.44 sq km (108.7 acres), the Vatican State is comparable in size to a small farm in Ireland and easily outpaced by Europe's next smallest states, Monaco and San Marino.
The sovereign territory is so tiny that any visitor to St Peter's and the Vatican Museums visits the state many times over, constantly stepping in and out of Vatican and Italian territory.
But Vatican sovereignty also extends to 13 other buildings speckled across Rome.
These extraterritorial anomalies include Castel Sant'Angelo, a number of historical papal places, including the Lateran Palace and the Palace of the Holy Office, significant basilicas, including St John Lateran, St Mary Major and St Paul Outside the Walls, and some pontifical colleges, including Propaganda Fide close to the Spanish Steps and the Gregorian University.
Extraterritorial status even extends beyond Rome to Castel Gandolfo, the Pope's summer residence in the Alban Hills, and the adjoining Villa Barberini.
Other properties outside Rome ceded to the Holy See include the Basilica of St Francis in Assisi, St Anthony's Basilica in Padua, the Basilica of the Holy House in Loreto, and an area in Cesano, north of Rome, where Vatican Radio's controversial antennae are located.
Because these extraterritorial places are outside Italian jurisdiction, tourists can buy Vatican stamps and use the Vatican postal system in St John Lateran and St Mary Major, or find lower Vatican taxes mean cheaper drinks in the bars in Castel Sant'Angelo and at St Paul's Outside the Walls.
Inside the walls of St Peter's, the Swiss Guards and Vatican police ensure only Vatican employees top up with cheaper petrol at the Vatican's own filling station.
But the few privileged visitors to the Vatican Gardens can enjoy the high-class, low-tax shopping facilities in a former train station.
Because the Vatican has a small resident population but millions of visitors each year, St Peter's is a paradise for pickpockets and purse snatchers and the Vatican has the highest per capita crime rate of any nation - more than 20 times higher than Italy's, according to the Vatican's chief prosecutor, Nicola Picardi.
The perpetrators are visitors too and are rarely caught, with 90 per cent of crimes unsolved.
Other crimes included embezzlement, fraud and insulting the police and civil servants, although the last serious crime was in 1998 when a disgruntled Swiss Guard shot dead his commander and the commander's wife before killing himself.
Every tourist wants to be photographed with the Swiss Guards in their Renaissance-style striped uniforms.
Popular myth says the uniforms, in the traditional blue, red and yellow of the Medici, were designed by Michelangelo, but they are only 100 years old and were designed in 1905 by a Swiss Guard commandant inspired more by scenes in the Raphael Rooms than by Michelangelo.
The guards, who stand watch from the outer gates of the Vatican to the doors to the Pope's private apartments, are limited by law to 100 soldiers, who are male Swiss Catholics who have finished basic training in the Swiss army, are fluent in five languages, aged 19-30 and stand at least 174cm (5ft 9in) tall.
New guards take an oath to "faithfully, loyally and honourably serve the supreme pontiff and his legitimate successors with all my strength, sacrificing if necessary also my life to defend them."
They are fully trained with the sword and halberd, but since the attempted assassination of Pope John Paul II in 1981, a stronger emphasis is placed on functional, non-ceremonial roles and Swiss Guards are now trained in unarmed combat and issued with SIG P 75 pistols and Heckler and Koch submachine-guns.
Rome's secular authorities spent €8 million this year on events around the death of Pope John Paul and the inauguration of Pope Benedict XVI, when four million pilgrims visited the city.
Tourist figures in Rome were up 10 per cent this summer, but the 20 million tourists in Rome each year are a drain on the finances of a city struggling.
With a national cap on public spending and the high costs of restoring historic buildings, maintaining public transport and cleaning up the city, some proposed solutions include a nightly bed tax.
Eternal problems eternally beset the Eternal City.