The Julio-Claudian family would have received training from private tutors, mostly on the subject of Latin. The written and spoken Latin language was the basis and substance of a good Roman education. Aristocrats had to know how to write well and speak well. The tutors were usually slaves or former slaves and were oppressively cruel. Beatings were frequent. Some scholars speculate that this may help explain the unnatural cruelty perpetrated by so many Romans as adults. Caligula spent many of his younger years with his father while stationed throughout the empire.