The Celts were an Indo-European people and in their religion one can find many similarities with Latin, Greek and even Hindu gods. Celtic deities resembled humans who displayed human weaknesses and sins. The Celts believed their gods to be their ancestors, not their creators. The Celts believed their origins lay with the mother goddess, Danu, who fell from heaven and created the river Danube. They believed humans consisted of a body, soul and spirit, and the world was divided into earth, sea and air. Many Celtic religious and philosophical concepts of the world were divided up in trinities. It is thought that this strongly influenced the later Christian belief of the Holy Trinity.

The human head was seen as the source and power of the spirit. It was a mark of great might if they took the head of an enemy they admired, embalmed it in cedar oil and kept it as a prized possession. Celts believed that after death the soul would be reborn into the Otherworld: when a soul in the Otherworld died it would be reborn into this world. To give the dead a good start in the Otherworld the Celts buried them with rich goods such as jewelry, clothes, weapons, food, and drink. One day of each year, on October 31, members of the Otherworld would be visible in this world. This was the day when the dead could come back to haunt the living who had wronged them. It is still known to us as the feast of Samhain, Halloween, or All Souls' Day.

Celtic culture has had a deep influence on European society and religion. Versions of their language are still spoken in parts of France, England and Ireland. Back around 100 BC Celtic craftsmen anticipated many of the tools we use today, such as the plough, and many names of European towns and rivers are derived from Celtic names.

Women were well respected in Celtic society. In early Celtic culture there were many great women warriors and queens, and in tribal gatherings they had an equal vote. In contrary to Greek and Roman women, Celtic women had property rights. Women and men had equal rights to divorce: there is even an example of an Irish law that permitted a woman to divorce her husband if he snored.

The Celts had a vast trade network all across Europe. They traded metalwork, salt, grains and horses with the Romans in return for wine, and luxury goods. Their inventions in metal tools and weapons as well as agricultural techniques made them flourish.

In battle Celtic warriors would line up in front of the enemy army, and scream and bash their swords on their shields as they came charging into the enemy lines. With this strategy they hoped to scare their enemy since it is much easier to attack a fleeing soldier. When the enemy remained firm, the Celts would realign and start the intimidation ritual all over again. They painted and tattooed their bodies with fantastic designs, put glue in their hair so that it would stick up in long peaks, and wore long drooping mustaches. In battle they would wear brightly colored tartan pants or go completely naked apart from body paint. Even though the puritan Romans thought of them as revolting primitives, they still admired their extreme courage and strength as warriors. When they weren't fighting the Greeks or Romans, the Celts were often feuding amongst each other.

The Celts were also master craftsmen. They were the first people in Europe to work with iron, making tools, weapons and jewelry. The artifacts that were found by archeologists show a unique style. Celtic craftsmen and artists liked to use plant and animal motifs, as well as more abstract curves and spirals. These patterns were found on shields, swords, vessels, drinking cups and jewelry.