Darksaber/Legends

Pre Clone Wars
Sometime before the Clone Wars, the lightsaber belonged to one of the Jedi on the Temple on Coruscant. The weapon would them be stolen by Pre Vizsla's ancestors and would be passed down from generation to generation, eventually falling into his possession.

Clone Wars
During the Clone Wars, Obi-Wan Kenobi would arrive to Mandalore to investigate rumors of conspiracy surrounding Duchess Satine. Later vizsla would equip the weapon and remark to Kenobi that the weapon had been stolen by his ancetors, and it eventually fell into his possession. He would then ignite the lightsaber, revealing the saber to be black, and the two men fought.