The Celts practised human sacrifice on a limited scale as part of their religious rituals. Animal sacrifice was more commonplace along with ritual deposition of tools weapons and jewellery. The evidence for human sacrifices comes from:

• Writings by Romans and Greeks often at second hand or hearsay
• Irish medieval texts
• Archaeological data

All these sources are open to interpretation and subject to bias however.

Julius Caesar wrote in his Gallic Wars:

[The Gauls] believe that unless a man's life is paid for by another man's, the majesty of the immortal gods cannot be appeased. They use figures of immense size, whose limbs, woven out of twigs, they fill them with living men and set on fire, and the men perish in a sheet of flame. They believe that the execution of those who have been caught in the act of theft or robbery is more pleasing to the immortal gods; but when the supply of victims fails they resort to the execution even of the innocent

Ritualised decapitation survives in the archaeological record such as the example of 12 headless corpses at the French late Iron Age sanctuary of Gournay-sur-Aronde .

Lindow man may be an example of a human sacrifice from the 1st or 2nd century CE, preserved in a peat bog in near perfect condition. The case for his sacrifice hinges on the three separate injuries he suffered. He was throttled, clubbed around the head and had his throat slit. This dovetails with the three-fold death detailed in medieval texts. Tollund man has also been suggested as a bog sacrifice although both men may also have been executed criminals.

Iron Age societies may have developed highly ritualised judicial killings in order to both satisfy their gods and punish wrongdoers at the same time.

See also: Celtic mythology