The Lambton Worm - Origins

The early Egyptians worshipped a holy crocodile (the Messeh). Over the years, this became a Dragon, which, in turn, became the sign of kingship. This eastern idea of a dragon influenced the Celtic tribes who invaded Briton and the Celtic kings in Britain were known as "Pendragons".

Heroes in Roman and Greek mythology fought with dragons. The Greek word drakon meant "one who sees" or "sharp-sighted one" and at first was a large serpent as well as "dragon".  The ancient Norsemen carved dragons on their ships and dragons were drawn on the shields of Anglo-Saxon tribes. The Chinese people
also had a dragon mythology. In China, the dragon was seen as a symbol of good fortune.

In the west, however, dragons are not usually seen as so friendly. English dragons were often known as worms; with long scaly bodies, short legs, or no legs at all, and often no wings. They were slimy and
killed with poisonous breath rather than fire. 'Worm' is dragon in Old English.

Sources:  http://myths.e2bn.org