Conversation so far:
When did Thomas Aquinas go to Paris?
In 1245 Thomas was sent to study at the Faculty of the Arts at the University of Paris, where he most likely met Dominican scholar Albertus Magnus
What did Thomas Aquinas study in Paris?
Then in 1252 he returned to Paris to study for the master's degree in theology.
Did Thomas Aquinas study under Magnus?
In 1245 Thomas was sent to study at the Faculty of the Arts at the University of Paris, where he most likely met Dominican scholar Albertus Magnus
What did Thomas Aquinas do instead becoming an abbot?
Thomas followed Albertus Magnus, declining Pope Innocent IV's offer to appoint him abbot of Monte Cassino as a Dominican. Albertus then appointed the reluctant Thomas magister studentium.

Question: Does that mean he was a student?
Self-contained rewrite: Does magister studentium mean Thomas Aquinas was a student?