The Adrian IV and her sister ships Pius XIV and St. Peter were the last three JumpShips to survive in service to the Holy See of the Catholic Church based out of Vatican City on Terra and the Ducal Palace on Alarion in the wake of the coup launched by Stefan Amaris in 2765 to seize control of the Terran Hegemony in 2765.
Stefan Amaris worked to directly subsume the authority and influence of the major religions based on Terra, destroying holy sites such as the Wailing Wall and torturing and executing senior religious figures, despoiling sites such as Mecca in the process. The Catholic Church knew that it would be a target for Amaris and his regime, and Oberst Andreas Kosovskaia, head of the Pontifical Swiss Guards, was entrusted by the Pope with an important mission - hiding the various treasures of the Vatican, particularly the contents of the Bibliotheca Apostolica Vaticana and the Archivum Secretum Vaticanum - the Vatican Library and the Vatican Secret Archives, respectively.
Oberst Kosovskaia was diligent in his efforts; when Stefan Amaris arrived in his personal DropShip accompanied by Rim Worlds infantry to seize the treasures of Vatican City, he found that the vast majority of what he wanted had disappeared. Furnishings, paintings and other such treasures had vanished along with a portion of the Ducal Guard, who had merged into the civilian population of the megacity of Rome. Amaris was furious, and Oberst Kosovskaia was the first to die when Rim Worlds infantry stormed the Papal quarters; Amaris then ordered the Pope and the College of Cardinals to watch as his forces demolished the Sistine Chapel, before the Pope and Cardinals were summarily executed.
The vanished treasures didn't remain in Rome for long, however. The two officers who were second in command to Oberst Kosovskaia - Oberstleutnant Chaeryl Brunegg on Terra and Oberstleutnant Daniel Nikolaus on Alarion - spent twelve months smuggling the various treasures out of Rome and off Terra to the Ducal Palace on Alarion. Oberstleutnant Brunegg accompanied the last load of books and sculptures to Alarion; the Swiss Guard gathered on Alarion felt that Amaris' reign indicated the decline of human civilization and that humanity would soon tear itself apart in the warfare they saw as inevitable. As such, the Swiss Guard hatched a plan; they, their families and the treasures rescued from Terra would retreat into the Deep Periphery aboard the Adrian IV and her two sister ships. Safe in the Deep Periphery, they would wait out the End of Days, returning after the Devil had claimed his share of souls, at which point they would help rebuild the Catholic Church.
The Adrian IV, Pius XIV and St. Peter departed Alarion in December 2766 and vanished from Inner Sphere records. The first organized search for the Swiss Guard began in the 2990s, when the exploration organization Interstellar Expeditions received funding for annual operations to investigate from a trust fund established by a wealthy benefactor. Over the course of the next hundred years Interstellar Expeditions managed to piece together much detail about what had happened to the Adrian IV and her sister ships, although by 3095 the final fate of the three ships was still unknown.
What Interstellar Expeditions had confirmed was that the Swiss Guard left the Inner Sphere via a series of uninhabited systems, in which they recharged their K-F Drives and topped up their supplies of food and water. Evidence from trash heaps discovered on worlds in two separate systems in the Free Worlds League and definitively identified as being from the Swiss Guard fleet gave indications of the route taken; the evidence included a document torn from one of the pages of a logbook belonging to a DropShip attached to the St. Peter, among other items. These findings showed that the Swiss Guard had charted a course that took them rimward and anti-spinward.
Interstellar Expeditions were able to investigate remains discovered on the world of Algenib in 3014 that were also tied to the Swiss Guard. Algenib had only recently been colonized by the Marian Hegemony, and the settlers had discovered man made artifacts; Interstellar Expeditions mounted a survey that discovered a mass grave, in which was found a large Ferro-Aluminum cross. The survey team exhumed and autopsied the bodies, one of which was still dressed in the uniform of a member of the Swiss Guard. The autopsies determined that the bodies were those of people who had all died as a result of smoke inhalation, severe burns or rapid decompression, indicating that they were probably the victims of an accident aboard a DropShip. The body in uniform was determined to be that of Oberstleutnant Brunegg by genetic testing.
Eighteen years later in 3032 Interstellar Expeditions stumbled across the human colonies in the system discovered to be named St. Andreas by accident. Located a hundred and fifty light years further out into the Deep Periphery than Algenib, the system consisted of a red giant star with a single planet in orbit; light emissions observed by accident led to the discovery of a city on the single planet and small settlements on both moons, and further investigation revealed the inhabitants to be the descendants of the Swiss Guard. The planet had been named St. Tomalin, while the two moons were named St. Chearyl and St. Daniel; the two moon settlements were built around underground complexes and domes linked to permanently grounded and partially cannibalized DropShips, while the city on St. Tomalin had at its heart the Priory, a large keep occupied by the planetary ruler, the Prior General, which was in turn built around the remains of a grounded Mule-class DropShip still emblazoned with the coat of arms of the Holy See.
Other Star League artifacts found on St. Tomalin all pointed to the long-vanished Swiss Guard fleet; the Prior General and the ruling class all wore replica Swiss Guard uniforms, carefully maintained the same Mauser 960 firearms used by the Swiss Guard, spoke Latin as their primary language and believed their fate and duty was to wait for the return of three figures - St. Andreas, St. Chaeryl and St. Daniel - who would return in the Vatican's JumpShips when the time came for the Guard to return to Rome. However, there were various oddities that Interstellar Expeditions couldn't explain; the residents of St. Andreas rebuffed questions about the lost treasures by simply pointing to their small collection of books in the library on St. Tomalin, and the two communities located on the moons, while fully aware of the existence of the city on St. Tomalin, showed no interest in traveling to the planet. The number of DropShips counted between the two moon colonies also only accounted for half the total number of DropShips the Adrian IV and her sister ships had taken out of the Inner Sphere.
With little progress made on St. Andreas, Interstellar Expeditions continued to search for the Adrian IV and the other ships; the most significant discovery that had been made since the discovery of the existence of the Society of St. Andreas was again made by accident, this time in 3088, when an Interstellar Expeditions team was exploring an uncharted system some fifty-five light years from St. Andreas and chanced across a partial jump sail bearing the coat of arms of the Holy See. The final fate of the Adrian IV remains a mystery.
- Interstellar Players 3: Interstellar Expeditions, p. 59-60, "Society of St. Andreas"