Yes he did, as a matter of fact Plagueis was the master of Sideous. Unfortunately, Plagueis was the best Sith Lord around, and he told all he knew to Sideous. Then Sideous knew all about Plagueis and the past of the Jedi and Sith. Sideous, wanting to be the new Sith Lord, had killed Plagueis in his sleep, now leaving Sideous with all of the knowledge of Plagueis. So Plagueis was murdered by Sideous and that is how it had happened.
Not much is known about Darth Plagueis. One thing I know is that Darth Plagueis's species was a Muun, but no one knows who his master was
Darth Plagueis' master's name was the Sith Lord Darth Tenebrous.
Dart Plagues the Wise (not whites) was a Sith Lord who developed the power to keep people he cared about alive but he never used it himself. He trained his apprentice in the most brutal ways constantly making his apprentice face his fears and things he hated. The Sith Lord's apprentice (Palpatine aka Darth Sideous) was very eager to discover the secret. Eventually the Sith Lord was getting old and told Sideous the secret to immortality with Sideous aware of the secret he did not need his master anymore and killed him in his sleep. He had the power to escape death but couldn't escape his own.
Darth Plagueis's master has never been named or revealed.
He was Darth Sideous' apprentice.
It was widely assumed that Palpatine's master was Darth Plagueis.
Darth Plagueis
Lord (Darth) Sidious
I think Palpatine
Darth Maul Apprentice of Darth Sideous
Khameir Sarin
Darth Sideous' alter ego is Emperor Paltapine.