Chosen answer:We have no particularly accurate way of telling how long Maul was his apprentice, although it's stated that Maul was trained as a Sith from a very young age, so it was probably some considerable time. As far as we know, Tyranus became the apprentice after Maul's death, so he held the position for roughly thirteen years. Vader then took over, holding the position until the events of Return of the Jedi, a period of about twenty-two years.
Chosen answer: We have no particularly accurate way of telling how long Maul was his apprentice, although it's stated that Maul was trained as a Sith from a very young age, so it was probably some considerable time. As far as we know, Tyranus became the apprentice after Maul's death, so he held the position for roughly thirteen years. Vader then took over, holding the position until the events of Return of the Jedi, a period of about twenty-two years.
Tailkinker ★