AR denier, 17mm, .9gr. Obv: +LVDOVICVS IMP, central cross with four besants. Rev: +XPIANA RELIOIO, central temple over two bars. 11th C. Mint Abbey of St. Maurice d'Agaune. Imitating Louis the Pious. Louis the Pious affirmed the abbey's minting rights, which date from the 7th C according to Dupont-Lachenal. These rights continued after Louis the Pious as control of the territory changed hands. The territory was part of Burgundy for a time and them became part of Savoy. In the 11th C this was Burgundian territory. Rudolph III used the abbey Chancellery and the abbey had the notary rights (the ability to record legal documents - a lucrative franchise). The abbey is located in territory that became Switzerland. It is in the SW corner of the county of Valais. R4887 matches the reverse. Looking for help cataloguing this coin. The coin was in my pocket when we visited the abbey, making this a nice example of planned physio-temporal asynchroneity. :)
The Abbey of St. Maurice dates from the 6th C, when it was founded by Sigismond of Burgundy. The abbey was built on the site of an earlier church that hds been constructed in the 4th C. That earlier site marked the burial place for St. Maurice and others from his Theban legion. Maurice was a Roman soldier who had been transferred from Egypt to the Gallic frontier. There he apparently refused to fight other Christians. The story goes that Emperor Maximilian ordered a decimation of the legion as a punishment. When they still wouldn't fight Christians, he ordered another decimation. Finally, in the face of further resistance, he ordered the balance of the legion slaughtered. The actual site of the massacre is to the south of St. Agaune. It'is location is not precisely known.
The abbey's fortunes flourished and waned over the centuries. It was sacked by a Saracen raid. It flourished during the high Middle Ages and suffered the decay as did many abbeys at other times. It generally benefited by being on a major transalpine route.
The abbey on the site today been reconstructed many times. This picture shows the current abbey, both a side view and from the top down. The picture from the top down is not difficult to take, since the abbey is built at the side of a cliff. Overall, the site is impressive. It is built in the narrow defile of St. Agaune, and is on the critical path from Lake Leman to the Great St. Bernard Pass. As such, it guards a major alpine route used since early times.

It is possible to get an idea of the extent of the constant reconstruction in the next schematic, which shows a series of different churches, many being superimposed on the ruin visible above. The text is not clear but the evolution of the site is. 'C' is the 4th and 5th C baptistery, ''A the 5th and 6th C churches, ''B the crypt of St. Maurice built on between the 4th and 8th C. The current church dates from the 17th C and the tower visible above dates from the 11th C.

The catacombs survive and are pictured below. Eugene Cox, in The Green Count, recounts an interesting story about the catacombs of the abbey. In 1365 HRE Emperor Charles IV was visiting Savoy with count Amedeus VI. The emperor, learning that the abbey was not too far from Lake Leman, asked to visit it. This required a trip over the col de Morgins. Charles wanted to, among other things, visit the burial site of an ancestor, St. Sigismond. From Cox:
"The abbot and monks of St. Maurice received their visitor with pleasure but declared themselves confounded when he asked to see the tomb of the holy Sigismond. "Seigneurs," replied the abbot, '"the church we know well but are ignorant of the location of the sepulchre." Undaunted, Charles asked to see the chapel in which the tomb was supposed to have been. ... The the emperor "brought out an ancient chronicle which contained the life of St. Sigismond and the story of how he had been buried and walled up in an underground chapel." Having read the account aloud, he ordered the monks to bring torches and picks and led them down into the vault under the chapel. Charles told them where to dig and they had hardly begun when part of the wall fell away, revealing a cave containing the remains of St. Sigismond ...The monks were astonished and delighted and began to sing hymns and praises to God. The emperor, equally pleased, claimed as his reward the venerable skull for his relic collection..."

The remains were placed in ''a splendid guilt coffer with a handsomely sculpted exterior." The modern abbey has a chapel dedicated to St. Sigismond and a reliquary with his remains, but I am unsure if this is the one that dates to the 14th C. The chapel is pictured on the left and reliquary on the right.
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Cox goes on to say that while there Charles IV also wanted to see the body of St. Maurice, "His veneration for this saint was so great that only with difficulty could the Green Count prevent the Emperor from dismembering this skeleton also in order to carry more relics back to Prague with him. Amedeus finally permitted his illustrious guest to take away the saint's battle axe, in place of his bones."
The abbey also has a 'tresor' with a number of interesting items dating to early Carolingian times. Pictures below, on the left, is a pitcher said to date from Charlemagne and on the right two 12th C reliquaries.
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The final picture again shows the abbey, with an emphasis on chapel at the south end of the church, where the chapel of St. Sigismond is located, and the the 11th C tower.

Sources:
Cox, The Green Count
Dupont-Lachenal, Saint Maurice D'Agaune
Roduit and Stucky, La Basilique de l'Abbaye de Saint Maurice