Hadrian's Wall in the context of Horreum

The Britons (*Pritanī, Latin: Britanni, Welsh: Brythoniaid), also known as Celtic Britons or ancient Britons, were the Celtic people who inhabited Great Britain from at least the British Iron Age until the High Middle Ages, at which point they diverged into the Welsh, Cornish, and Bretons (among others). They spoke Common Brittonic, the ancestor of the modern Brittonic languages.

The earliest written evidence for the Britons is from Greco-Roman writers and dates to the Iron Age. Ancient Britain was made up of many tribes and kingdoms, associated with various hillforts. The Britons followed an ancient Celtic religion overseen by druids. Some of the southern tribes had strong links with mainland Europe, especially Gaul and Belgica, and minted their own coins. The Roman Empire conquered most of Britain in the 1st century AD, creating the province of Britannia. The Romans invaded northern Britain, but the Britonnic tribes such as the Caledonians and Picts in the north remained unconquered, and Hadrian's Wall which bisects modern Northumbria and Cumbria became the edge of the empire. A Romano-British culture emerged, mainly in the southeast, and British Latin coexisted with Brittonic. It is unclear what relationship the Britons had with the Picts, who lived outside of the empire in northern Britain; however, most scholars today accept the fact that the Pictish language was closely related to Common Brittonic.

A defensive wall is a fortification usually used to protect a city, town or other settlement from potential aggressors. The walls can range from simple palisades or earthworks to extensive military fortifications such as curtain walls with towers, bastions and gates for access to the city. From ancient to modern times, they were used to enclose settlements. Generally, these are referred to as city walls or town walls, although there were also walls, such as the Great Wall of China, Walls of Benin, Hadrian's Wall, Anastasian Wall, and the Atlantic Wall, which extended far beyond the borders of a city and were used to enclose regions or mark territorial boundaries. In mountainous terrain, defensive walls such as letzis were used in combination with castles to seal valleys from potential attack. Beyond their defensive utility, many walls also had important symbolic functions – representing the status and independence of the communities they embraced.

Existing ancient walls are almost always masonry structures, although brick and timber-built variants are also known. Depending on the topography of the area surrounding the city or the settlement the wall is intended to protect, elements of the terrain such as rivers or coastlines may be incorporated in order to make the wall more effective.

The Antonine Wall (Latin: Vallum Antonini) was a turf fortification on stone foundations, built by the Romans across what is now the Central Belt of Scotland, between the Firth of Clyde and the Firth of Forth. Built some twenty years after Hadrian's Wall to the south, and intended to supersede it, while it was garrisoned it was the northernmost frontier barrier of the Roman Empire. It spanned approximately 63 kilometres (39 miles) and was about 3 metres (10 feet) high and 5 metres (16 feet) wide. Lidar scans have been carried out to establish the length of the wall and the Roman distance units used. Security was bolstered by a deep ditch on the northern side. It is thought that there was a wooden palisade on top of the turf. The barrier was the second of two "great walls" created by the Romans in Great Britain in the second century AD. Its ruins are less evident than those of the better-known and longer Hadrian's Wall to the south, primarily because the turf and wood wall has largely weathered away, unlike its stone-built southern predecessor.

Construction began in AD 142 at the order of Roman Emperor Antoninus Pius. Estimates of how long it took to complete vary widely, with six and twelve years most commonly proposed. Antoninus Pius never visited Britain, unlike his predecessor Hadrian. Pressure from the Caledonians probably led Antoninus to send the empire's troops farther north. The Antonine Wall was protected by 16 forts with small fortlets between them; troop movement was facilitated by a road linking all the sites known as the Military Way. The soldiers who built the wall commemorated the construction and their struggles with the Caledonians with decorative slabs, twenty of which survive. The wall was abandoned only eight years after completion, and the garrisons relocated rearward to Hadrian's Wall. Most of the wall and its associated fortifications have been destroyed over time, but some remains are visible. Many of these have come under the care of Historic Environment Scotland and the UNESCO World Heritage Committee.

A wax tablet is a tablet made of wood and covered with a layer of wax, often linked loosely to a cover tablet, as a "double-leaved" diptych. It was used as a reusable and portable writing surface in antiquity and throughout the Middle Ages. Cicero's letters make passing reference to the use of cerae, and some examples of wax-tablets have been preserved in waterlogged deposits in the Roman fort at Vindolanda on Hadrian's Wall. Medieval wax tablet books are on display in several European museums.

Writing on the wax surface was performed with a pointed instrument, a stylus. A straight-edged spatula-like implement (often placed on the opposite end of the stylus tip) would be used as an eraser. The modern expression of "a clean slate" equates to the Latin expression "tabula rasa".

The Britons (*Pritanī, Latin: Britanni, Welsh: Brythoniaid), also known as Celtic Britons or ancient Britons, were the Celtic people who inhabited Great Britain from at least the British Iron Age until the High Middle Ages, at which point they diverged into the Welsh, Cornish, and Bretons (among others). They spoke Common Brittonic, the ancestor of the modern Brittonic languages.

The earliest written evidence for the Britons is from Greco-Roman writers and dates to the Iron Age. Ancient Britain was made up of many tribes and kingdoms, associated with various hillforts. The Britons followed an ancient Celtic religion overseen by druids. Some of the southern tribes had strong links with mainland Europe, especially Gaul and Belgica, and minted their own coins. The Roman Empire conquered most of Britain in the 1st century AD, creating the province of Britannia. The Romans invaded northern Britain, but the Britonnic tribes such as the Caledonians and Picts in the north remained unconquered, and Hadrian's Wall (which bisects the modern English counties of Northumberland and Cumbria) became the edge of the empire. A Romano-British culture emerged, mainly in the southeast, and British Latin coexisted with Brittonic. It is unclear what relationship the Britons had with the Picts, who lived outside of the empire in northern Britain; however, most scholars today accept the fact that the Pictish language was closely related to Common Brittonic.

Britannia Inferior (Latin for "Lower Britain") was a new province carved out of Roman Britain probably around AD 197 during the reforms of Septimius Severus although the division may have occurred later, between 211 and 220, under Caracalla. The removal of the governors in Londinium from control over the legions guarding Hadrian's Wall was aimed at reducing their power, given Clodius Albinus's recent bid to become emperor. The province was probably formalised around 214 by Severus's son Caracalla.

Including most of modern northern England and the Midlands, the region was governed from the city of Eboracum (modern York) by a praetorian legate in command of a single legion stationed in the city. This subdivision of Britannia lasted throughout the Severan dynasty until the reorganisation of the empire under Diocletian in 296.

Defensive walls are a feature of ancient Roman architecture. The Romans generally fortified cities, rather than building stand-alone fortresses, but there are some fortified camps, such as the Saxon Shore forts like Porchester Castle in England. City walls were already significant in Etruscan architecture, and in the struggle for control of Italy under the early Republic many more were built, using different techniques. These included tightly fitting massive irregular polygonal blocks, shaped to fit exactly in a way reminiscent of later Inca work. The Romans called a simple rampart wall an agger; at this date great height was not necessary. The Servian Wall around Rome was an ambitious project of the early 4th century BC. The wall was up to 10 metres (32.8 ft) in height in places, 3.6 metres (12 ft) wide at its base, 11 km (7 mi) long, and is believed to have had 16 main gates, though many of these are mentioned only from writings, with no other known remains. Some of it had a fossa or ditch in front, and an agger behind, and it was enough to deter Hannibal. Later the Aurelian Wall replaced it, enclosing an expanded city, and using more sophisticated designs, with small forts at intervals.

The Romans walled major cities and towns in areas they saw as vulnerable, and parts of many walls remain incorporated in later defences, as at Córdoba (2nd century BC), Chester (earth and wood in the 70s AD, stone from c. 100), and York (from 70s AD). Strategic walls defending the frontiers of the Empire by running across open country were far rarer, and Hadrian's Wall (from 122) and the Antonine Wall (from 142, abandoned only 8 years after completion) are the most significant examples, both on the Pictish frontier. Most defences of the borders of the Roman Empire relied on systems of forts and roads without attempting a continuous barrier.

A castellum in Latin is usually:

• a small Roman fortlet or tower, a diminutive of castrum ('military camp'), often used as a watchtower or signal station like on Hadrian's Wall. It is distinct from a burgus, which is a later Latin term that was used particularly in the Germanic provinces.
• a distribution, header, and settling tank for municipal water in a Roman aqueduct (known as a castellum aquae/castellum divisorium).

It is the source of the English word "castle".

Carlisle (/kɑːrˈlaɪl/ kar-LYLE, locally /ˈkɑːrlaɪl/ KAR-lyle; from Cumbric: Caer Luel) is a city located in the Cumberland district of Cumbria, England. It is the largest settlement and only city in Cumbria. In 2021 it had a population of 77,730.

Carlisle's early history is marked by the establishment of a settlement called Luguvalium to serve forts along Hadrian's Wall in Roman Britain. Due to its proximity to Scotland (being located eight miles or thirteen kilometres south of the current Anglo-Scottish border), Carlisle Castle and the city became an important military stronghold in the Middle Ages. The castle served as a prison for Mary, Queen of Scots in 1568 and currently hosts the Duke of Lancaster's Regiment and the Border Regiment Museum. A priory was built in the early 12th century, which subsequently became Carlisle Cathedral in 1133 on the creation of the Diocese of Carlisle. As the seat of a diocese, Carlisle therefore gained city status. Carlisle also served as the county town of the historic county of Cumberland from the county's creation in the 12th century.

The Stanegate (meaning "stone road" in Northumbrian dialect) was an important Roman road and early frontier built in what is now northern England. It linked many forts including two that guarded important river crossings: Corstopitum (Corbridge) on the River Tyne in the east (situated on Dere Street) and Luguvalium (Carlisle) on the River Eden in the west. The Stanegate ran through the natural gap formed by the valleys of the River Tyne in Northumberland and the River Irthing in Cumbria. It predated the Hadrian's Wall frontier by several decades; the Wall would later follow a similar route, albeit slightly to the north.

The Stanegate should not be confused with the two Roman roads called Stane Street in the south of England, namely Stane Street (Chichester) and Stane Street (Colchester). In both these cases the meaning is the same as for the northern version, indicating a stone or paved road.

The recorded history of Scotland begins with the arrival of the Roman Empire in the 1st century, when the province of Britannia reached as far north as the Antonine Wall. North of this was Caledonia, inhabited by the Picti, whose uprisings forced Rome's legions back to Hadrian's Wall. As Rome finally withdrew from Britain, a Gaelic tribe from Ireland called the Scoti began colonising Western Scotland and Wales. Before Roman times, prehistoric Scotland entered the Neolithic Era about 4000 BC, the Bronze Age about 2000 BC, and the Iron Age around 700 BC.

The Gaelic kingdom of Dál Riata was founded on the west coast of Scotland in the 6th century. In the following century, Irish missionaries introduced the previously pagan Picts to Celtic Christianity. Following England's Gregorian mission, the Pictish king Nechtan chose to abolish most Celtic practices in favour of the Roman rite, restricting Gaelic influence on his kingdom and avoiding war with Anglian Northumbria. Towards the end of the 8th century, the Viking invasions began, forcing the Picts and Gaels to cease their historic hostility to each other and to unite in the 9th century, forming the Kingdom of Scotland.

Pons Aelius (Latin for "Aelian Bridge"), or Newcastle Roman Fort, was an auxiliary castra and small Roman settlement on Hadrian's Wall in the Roman province of Britannia Inferior (northern England), situated on the north bank of the River Tyne close to the centre of present-day Newcastle upon Tyne, and occupied between the 2nd and 4th centuries AD.

Vindolanda was a Roman auxiliary fort (castrum) just south of Hadrian's Wall in northern England, which it pre-dated. Archaeological excavations of the site show it was under Roman occupation from roughly 85 AD to 370 AD. Located near the modern village of Bardon Mill in Northumberland, it guarded the Stanegate, the Roman road from the River Tyne to the Solway Firth. It is noted for the Vindolanda tablets, a set of wooden leaf-tablets that were, at the time of their discovery, the oldest surviving handwritten documents in Britain.