Nazareth were one of the "sweat bands" of the early 1970's. Hard Rock in the Led Zeppelin vein. Nazareth actually got started in the late 60's, the outgrowth from one of the many Beat Groups around at the time. But like their brethren Status Quo, switched from Beat/Psych/Pop to Hard Rock and paved the way for an eventual wave of Heavy Metal. But that's another era and another story.

Here is Nazareth just around the time they released Hair Of The Dog (an apt title for the amount of drinking going on). It was during this period of time they gained their biggest popularity in the U.S. and scored with several singles (most notably Love Hurts), but mostly their audience was FM Hard Rock and high voltage. This concert was recorded by the BBC in 1975 at the Paris Theater in London.

You can turn this up - but you probably don't need to be asked.