Diancecht was the Irish god of Healing and Medicine in Celtic culture during the Bronze age in Ireland. Diancecht was the son of Dagda, "the good god of the Irish Celts", and was the physician to the Tuatha De Danaan, the ruling clan of gods. His son, Miach, was also a healer but preferred to use incantations and herbs when healing which was at odds with his father's surgical methods.
Celtic Empire 700-100 BC -- This map does show the great extent to which Celtic culture had spread across Europe prior to the rise of Rome, but it misrepresents the implied power by calling it an empire. The Celts were never united into a single empire, but divided into hundreds of tribal clans of varying size and power. Had they ever effectively united, Rome may have had a much more difficult road to conquest.
The La Tène culture was a European Iron Age culture named after the archaeological site of La Tène on the north side of Neuenburgersee in Switzerland, where a rich cache of artifacts was discovered by Hansli Kopp in 1857. La Tène culture developed and flourished during the late Iron Age (from 450 BCE to the Roman conquest in the 1st century BCE) in Belgium, eastern France, Switzerland, Austria, Southern Germany, the Czech Republic, Poland, Slovakia, Slovenia, Hungary and Romania.