“Marley was dead: to begin with. There is no doubt whatever about that. The register of his burial was signed by the clergyman, the clerk, the undertaker, and the chief mourner. Scrooge signed it: and Scrooge’s name was good upon ‘Change, for anything he chose to put his hand to. Old Marley was as dead as a door-nail.”
Origin

Jacob Marley was the business partner of Ebenezer Scrooge, and like his partner he was a miser. He left no one to mourn him when he died, and he discovered upon entering the afterlife that he would be forced to carry weights and chains for eternity as penance for his sins in life. As part of that penance, he was allowed to go back and forewarn Scrooge to change his ways before he too was similarly condemned, and to inform his still-living partner of the impending visit of the three Ghosts of Christmas, Past, Present and Future.
Creation

Marley was created by Charles Dickens for the 1843 novel A Christmas Carol.