The Dying Gaul in the context of Attalus I Soter

The Celts (/kɛlts/ KELTS, see pronunciation for different usages) or Celtic peoples (/ˈkɛltɪk/ KEL-tik) were a collection of Indo-European peoples in Europe and Anatolia, identified by their use of Celtic languages and other cultural similarities. Major Celtic groups included the Gauls; the Celtiberians and Gallaeci of Iberia; the Britons, Picts, and Gaels of Britain and Ireland; the Boii; and the Galatians. The interrelationships of ethnicity, language and culture in the Celtic world are unclear and debated; for example over the ways in which the Iron Age people of Britain and Ireland should be called Celts. In current scholarship, 'Celt' primarily refers to 'speakers of Celtic languages' rather than to a single ethnic group.

The history of pre-Celtic Europe and Celtic origins is debated. The traditional "Celtic from the East" theory, says the proto-Celtic language arose in the late Bronze Age Urnfield culture of central Europe, named after grave sites in southern Germany, which flourished from around 1200 BC. This theory links the Celts with the Iron Age Hallstatt culture which followed it (c. 1200–500 BC), named for the rich grave finds in Hallstatt, Austria, and with the following La Tène culture (c. 450 BC onward), named after the La Tène site in Switzerland. It proposes that Celtic culture spread westward and southward from these areas by diffusion or migration. A newer theory, "Celtic from the West", suggests proto-Celtic arose earlier, was a lingua franca in the Atlantic Bronze Age coastal zone, and spread eastward. Another newer theory, "Celtic from the Centre", suggests proto-Celtic arose between these two zones, in Bronze Age Gaul, then spread in various directions. After the Celtic settlement of Southeast Europe in the 3rd century BC, Celtic culture reached as far east as central Anatolia, Turkey.

Attalus I (Ancient Greek: Ἄτταλος 'Attalos'), surnamed Soter (Greek: Σωτήρ, 'Savior'; 269–197 BC), was the ruler of the Greek polis of Pergamon (modern-day Bergama, Turkey) and the larger Pergamene Kingdom from 241 BC to 197 BC. He was the adopted son of King Eumenes I, whom he succeeded, and the first of the Attalid dynasty to assume the title of king, sometime around 240 to 235 BC. He was the son of Attalus and his wife Antiochis.

Attalus won an important victory, the Battle of the Caecus River, over the Galatians, a group of migratory Celtic tribes from Thrace, who had been plundering and exacting tribute throughout most of Asia Minor for more than a generation. The victory was celebrated with a triumphal monument at Pergamon (The Dying Gaul) and Attalus taking the surname "Soter" and the title of king. He participated in the first and second Macedonian Wars against Philip V of Macedon as a loyal ally of the Roman Republic, although Pergamene participation was ultimately rather minor in these wars. He conducted numerous naval operations throughout the Aegean, gained the island of Aegina for Pergamon during the first war and Andros during the second, twice narrowly escaping capture at the hands of Philip V. During his reign, Pergamon also repeatedly struggled with the neighboring Seleucid Empire to the east, resulting in both successes and setbacks.

A torc, also spelled torq or torque, is a large rigid or stiff neck ring in metal, made either as a single piece or from strands twisted together. The great majority are open at the front, although some have hook and ring closures and a few have mortice and tenon locking catches to close them. Many seem designed for near-permanent wear and would have been difficult to remove.

Torcs have been found in Scythian, Illyrian, Thracian, Celtic, and other cultures of the European Iron Age from around the 8th century BC to the 3rd century AD. For Iron Age Celts, the gold torc seems to have been a key object. It identified the wearer—apparently usually female until the 3rd century BC, thereafter usually but not exclusively male—as a person of high rank, and many of the finest works of ancient Celtic art are torcs. Celtic torcs disappeared in the Migration Period, but during the Viking Age torc-style metal necklaces, mainly in silver, came back into fashion. Similar neck-rings are also part of the jewellery styles of various other cultures and periods.