Old Time Music according to Wikipedia

[Ptarmigan]

Well this is what Wikipedia has to say about Old Time Music.

Wikipedia - Old Time Music

[john]

Hi Rick,
the word Hillbilly and hillbilly music comes from the band the hillbillies. They were dressed in rube garb for commercial photos and people thought ..well.. ok. Hillbilly Music.
Rockabilly, mountain Rock and Roll. And so on.
Just look it up!!!

[Ptarmigan]

Here's a photo of yer Hill Billies, John.

The Hill Billies

Here are four possible sources for this term. Are there any others, I wonder?

Cheers
Dick

The term "Hill-Billies" is first encountered in documents from 17th century Ireland.
Roman Catholic King James II landed at Kinsale in Ireland in 1689 and began to raise a Catholic army in an attempt to regain the British throne.
Protestant King William III, Prince of Orange, led an English counterforce into Ireland and defeated James II at the Battle of the Boyne in 1690.
A significant portion of William III's army was composed of Protestants of Scottish descent (Planters) who had settled in Ulster in northern Ireland.
The southern Irish Catholic supporters of James II referred to these northern Protestant supporters of King William as "Hill-Billies"[citation needed] and "Billy Boys"--Billy being an abbreviation of William.
It is believed that the term "hillbilly" in the United States was conferred during the early 18th century by the occupying British soldiers as a carry over from the Irish term, in referring to Scotch-Irish immigrants of mainly Presbyterian origin, dwelling in the frontier areas of the Appalachian Mountains[citation needed].
These Protestant Irish colonists brought their cultural traditions with them when they immigrated.
Many of their stories, songs and ballads dealt with the history of their Ulster and Lowland Scot homelands, especially relating the tale of the Protestant King William III, Prince of Orange.

[Ed. There are certainly plenty "Billy Boys" around here, in Ulster! ;D ]

Yet another explanation for the term comes from the European immigrants to the United States who settled in the Appalachian Mountains.
Many of these immigrants were of Germanic origin and were named Wilhelm with the short form Willy, a common Germanic name during that time.
Those Wilhelms, who went by Bill or Billy, living in the Appalachian Mountains became known as "hillbillies," i.e., Bills who lived in the hills.

Alternatively, it is also speculated that the term emerged as a derogatory nickname given by the coastal plain-dwelling Anglo-Saxon Southerners for the hill-dwelling settlers of Eastern Tennessee, Western Virginia (including modern West Virginia), northern Arkansas and Eastern Kentucky, many of whom were ambivalent to the Confederacy during the American Civil War[citation needed].

In Poland a hillbilly was reference to the people who live in the mountainous south of Poland in the part once occupied by the Austro-Hungarian Empire.

Hillbillies - Wikipedia

P.S. I can see how the term "Hill Wilhelms" just wouldn't have caught on so well! ;D