Question: What Roman-Britian province inhabited by Celtics Britons, Belgae and Picts, holds the best preserved Roam for north of the Alps?

Context articles: Trusham
Hen Ogledd
Caledonians
Battle of Coilsfield
Picts
Britannia
Hadrian's Wall
Portus Adurni
Teggiano
Children of Llullaillaco

Trusham is a small village in the Teign Valley just outside Chudleigh between Newton Abbot and Exeter in Devon.
 The name originates from the Celtic 'Trisma', considered by Ekwall to mean ‘brushwood’ or ‘fallen leaves’, became 'Trisme' for about four hundred years, and then in the 16th century 'Tryssame' or 'Trysham'.
 It has one pub - the Cridford Inn - probably the oldest pub/inn in Devon and possibly the oldest in England.
 It was quoted in "The Which Guide to Country Pubs" dated March 1988 that the main site of the now, Cridford Inn, dates back to 825AD - well before Alfred the Great and was originally inhabited by the early Britons/Celts.
 However, King Athelstan of the English notably expelled "that filthy race" (the Britons) from Exeter and the surrounding area, as far as Cornwall, in 927AD.
 The building was presumably remodelled in 1081, as a small cobbled area in which was set a crude mosaic, made of dolerite and quartz, bearing the initials HJ and the year 1081 was discovered during renovations in 1988.
 This mosaic is thankfully preserved and displayed under glass in the inn's restaurant.
 The Cridford had also previously served as a nunnery and a farm.
 In 1086 it is understood to be one of the nine small-holdings mentioned in the “Domesday Book”, and by then belonged to the Abbey of Buckfast in the Manor of Trusham.
 During the early 13th to 15th Centuries, the building itself was a farmhouse and the stained glass mullion window in the bar is from this period and is possibly the earliest surviving example of a Medieval domestic window in England.
 It is also believed that The Cridford Inn is home to two ghosts,; one is said to be a Nun from the very early history of the property and a second is a Cavalier from Trusham's conflict with Ashton, (a nearby village) during the Civil war of 1642-46.
 In more recent times, the buildings reverted to farm use and as a Devon Longhouse was previously known as Cridford Farm, the home of one branch of the Cridford family who have a long history in Devon.
 Members of the Cridford family still live in Devon.
Yr Hen Ogledd (] ), in English the Old North, is the region of Northern England and the southern Scottish Lowlands inhabited by the Celtic Britons of sub-Roman Britain and the Early Middle Ages.
 Its denizens spoke a variety of the Brittonic language known as Cumbric.
 The Hen Ogledd was distinct from the parts of northern Britain inhabited by the Picts, Anglo-Saxons, and Scoti as well as from Wales, although the people of the Hen Ogledd were the same Brittonic stock as the Picts, Welsh and Cornish, and the region loomed large in Welsh literature and tradition for centuries after its kingdoms had disappeared.
The Caledonians (Latin: "Caledones" or "Caledonii "; Greek: Καληδώνες , "Kalēdōnes") or the Caledonian Confederacy were a group of indigenous peoples of what is now Scotland during the Iron Age and Roman eras.
 The name is an exonym: the Ancient Greeks and Romans knew their territory as Caledonia and used the term vaguely in reference to its inhabitants.
 The Caledonians were initially considered to be a group of Britons, but were later distinguished as the Picts, a related people who nonetheless spoke a Brittonic language.
 The Caledonian Britons were enemies of the Roman Empire, which was the occupying force then administering most of Great Britain as the Roman province of "Britannia".
The Battle of Coilsfield was a semi-legendary clash in Ayrshire, Scotland, between an allied force of Picts and Scots under Fergus I and an army of Britons led by Coilus, the Coel Hen of the Welsh genealogies.
 The Britons had invaded Ayrshire and established a substantial camp on or near the banks of the River Doon, south of the town of Ayr.
 Place-names such as "Cynning Park", "North Park", "Gear Holm", "Wrights Field", "Slap-house" Burn, and most telling, "Cambusdoon", provide clues to the extent of the encampment and the numbers of men involved.
 Fergus allowed the Britons to languish in their camp well into winter, so as to exhaust their supplies and whittle down their numbers through disease and desertion.
 Taking advantage of a drunken Yule-tide revelry in the camp, the Picts and Scots attacked at night during the third watch.
 The camp, which had no ramparts or palisade, was successfully overrun.
 The army of Coilus fled the Doon-side camp in complete panic.
 After a circuitous retreat south around the "Craigs of Kyle", Fergus cornered the remnants west of the hamlet of Failford, and slaughtered Coilus and his men at the place now called Coilsfield.
 The few survivors rallied around the remnants of the baggage train, and after a brief truce, Fergus wisely allowed them to depart.
 Place-names in this area include "Dead-mens Holm", "The Bloody Burn", "Fergus-lea", "Cairn-gillan Hill", "Shackle Hill", and "King Coil's Grave", a Bronze-age burial mound.
The Picts were a tribal confederation of peoples who lived in what is today eastern and northern Scotland during the Late Iron Age and Early Medieval periods.
 They are thought to have been ethnolinguistically Celtic.
 Where they lived and what their culture was like can be inferred from the geographical distribution of brochs, Brittonic place name elements, and Pictish stones.
 Picts are attested to in written records from before the Roman conquest of Britain to the 10th century, when they are thought to have merged with the Gaels.
 They lived to the north of the rivers Forth and Clyde, and spoke the now-extinct Pictish language, which is thought to have been closely related to the Celtic Brittonic language spoken by the Britons who lived to the south of them.
Britannia was a Roman-Britain province inhabited by the Celtic Britons, Belgae and Picts, encompassing parts of the island south of Caledonia (roughly Scotland) of the geographical region of Great Britain and is the name given to the female personification of the island.
 It is a term still used to refer to the island.
 The name is Latin, and derives from the Greek form "Prettanike" or "Brettaniai", which originally designated a collection of islands with individual names, including "Albion" or Great Britain.
 By the 1st century BC, "Britannia" came to be used for Great Britain specifically.
 The Romans had initially called the entire provincial island "Britain" and it was only when the island was split into four provinces that two were given the name "Britannia".
 Although Britain had been designated part of the Roman Empire in 43 AD during the conquest of emperor Claudius it wasn't until the end of the 2nd century that Britannia had been pacified and fully adopted Roman practices.
Hadrian's Wall (Latin: "Vallum Aelium" ), also called the Roman Wall, Picts' Wall, or "Vallum Hadriani" in Latin, was a defensive fortification in the Roman province of Britannia, begun in AD 122 in the reign of the emperor Hadrian.
 It ran from the banks of the River Tyne near the North Sea to the Solway Firth on the Irish Sea, and was the northern limit of the Roman Empire, immediately north of which were the lands of the northern Ancient Britons, including the Picts.
Portus Adurni was a Roman fortress in the Roman province of Britannia situated at the north end of Portsmouth Harbour.
 Listed in the Notitia Dignitatum, it is generally accepted as having been located at grid reference [ SU624045] adjoining Portchester in the English county of Hampshire and was later converted into a medieval castle known as Portchester Castle.
 It is the best preserved Roman fort north of the Alps.
Teggiano (formerly called Diano) is a town and "comune" in Campania, Italy, in the province of Salerno.
 It is situated on an isolated eminence above the upper part of the valley to which it gives the name of Vallo di Diano.
Among the historic centers of the Province of Salerno, Teggiano is certainly one that has best preserved its ancient appearance of the fortress and it is this aspect which is shown to those who reach the old town.
 The natural appearance of Roman Oppidum, still now remembered by the well preserved plan of the Cardo and of the Decumanus, was renewed in the Norman period and in the age of Frederick II of Hohenstaufen.
The Children of Llullaillaco (] , ), also known as the Mummies of Llullaillaco, are three Inca child mummies rediscovered on 16 March 1999 by Dr. Johan Reinhard and his archaeological team near the summit of Llullaillaco, a 6739 m stratovolcano in the Andes mountains on the border between Chile and Argentina.
 The children were sacrifices in an Inca religious ritual that is believed to have taken place  1500 .
 In this ritual, the three children were drugged and allowed to freeze on top of the mountain, and then they were placed inside a small chamber 1.5 m beneath the ground, where they were left to die.
 According to Dr. Reinhard, the mummies "appear to be the best preserved Inca mummies ever found", and other archaeologists have expressed the same opinion, calling them among the best preserved mummies in the world.