Seven days after speaking to the shopkeeper, a league will appear in Cro Beska called the Historians. You must use four gladiators to fight an assortment of Minotaurs and Satyrs to complete the league. Afterwards either a minotaur (Langston) or satyr will offer to join your school. It is recommended that you save before this battle to ensure that you get the gladiator you want.
You can return to the shopkeeper in Cro Beska to recive the second part of the quest. This time it will occur in Syrna in another seven days. You must again fight an assortment of beasts, this time including a Cyclops. Afterwards another unit will offer to join your school, so saving is again recommended before the fight. It will either be a cyclops, satyr, or another minotaur. Recruiting the satyer is pointless as they are not rare, so taking another minotaur or the cyclops is recommended as they can not be recruited untill you reach the Expanse.