A collection of postcards sent from Ozzy Osbourne to his mother in the late 1960s is selling at Sheffield Auction Gallery.
The lot also features publicity posters and lyrics relating to Earth, Sabbath's first incarnation, and is valued at £2,000-3,000 ($2,577-3,865).
Ozzy Osbourne wrote these postcards to his parents from Europe
The band formed in Aston, Birmingham in 1968 and changed the name in 1969, after seeing the 1963 Boris Karloff movie Black Sabbath advertised outside a cinema.
Following the name change the band switched to playing a new, darker strain of music that came to be called heavy metal.
Ozzy's postcards to his mother date to the band's first European tour in 1968-1969.
One, sent from France, reads: "Arrived here safely, but it is not a very nice place, I don't think the people like long hair."
The remarkable collection was recovered from a building in London's Docklands in the 1980s.
Auctioneer Stephen Flintoft said: "Perhaps the most interesting item, among so many, is the handwritten lyrics headed 'by Earth' to the song Changing Phases, a title later changed to Solitude, which featured on the 1971 double platinum Black Sabbath album Master of Reality."
Please sign up to our free newsletter to receive exciting news about music memorabilia auctions.