In 1911, William Grattan Flood, a professor of music at National University of Ireland, researched and printed The Story of the Bagpipe. Professor Flood explored the instrument's early origin in the cradle of civilization, the Middle East, where he states the earliest date for the pipes is 4000 B.C., where a bagpipe is found in Chaldean sculptures. This evidence shows it is ancient, certainly as old as the harp and nearly as old as the drum. Greeks, Egyptians and Romans all marched to the skirl of the pipes to battle. This antiquity includes the ancient Hebrews as well.
Flood states that the word symphony actually referred to pipe music in the Middle Ages.
The bagpipe was even given place in the Brehan Laws of the 400s. It's also in reference to the hum that comes from the drones. After Christianity was embraced by the Irish, the bagpipe was used in church service to sustain the sacred chant or as a solo instrument. It is clear that the bagpipe existed in Ireland long before Scotland. The bagpipe is believed to have made its way to Scotland with the Dalradians upon their exodus from County Antrim across the Irish Sea at about 470 A.D., when Prince Fergus MacErc lead his clan in the invasion of the lands of the Picts at present Argyle.