Given his later career, Thomas must have received a relatively good education. Even if he had been intended to follow his father’s career, he would have needed to read and write—at least French and probably Latin—and calculate figures in Roman numerals, no mean task. In fact, he seems to have been destined for a clerical career from relatively early on, and to advance through the ranks of the clergy he would need not only Latin but training in theology and law. In his adolescence Thomas lived and studied at the priory of Merton for a while and also attended one or more grammar schools in London. He would have learned aristocratic manners—and he became notorious for his aristocratic demeanor—from Richer de l’Aigle, who used the Beckets’ home as his London residence. The story was later told that Thomas once nearly drowned when he fell into a millrace while out hawking with his patron.
Probably when he was in his early twenties, Thomas spent time in Paris, whose schools, just then developing into a university, were the center of theological study in twelfth-century Europe. It seems to have been a brief period, however, and Thomas certainly did not complete the course that would have entitled him to call himself magister (“master”), a title that conveyed that its holder was adept in Latin, theology, and Roman law. How well - or ill-educated Thomas was became a matter of controversy once he had been elevated to the archbishopric, and the debate has never ceased: his supporters portray him as fully capable of reading and writing the best Latin and of holding his own in theological and legal debate; his detractors portray him as struggling in all these matters, as dependent on his loyal clerical staff for the production of the sort of elegant, rhetorical Latin documents his position demanded, even as overly influenced by some of his supporters because he was not educated enough to fully understand some of the underlying issues in his quarrel with the king. Similarly, his supporters portray his departure from Paris as due to changing circumstances at home: his mother’s death, his father’s difficulties, the need for him to begin a career. His detractors, in contrast, portray him as never having intended to study seriously: Paris was, at most, a sort of finishing school intended to give him the polish he needed to make a career in the world, and he soon got bored with study. Certainly, some aspects of Thomas’s later career suggest that he knew that he was somewhat deficient in the niceties of written and spoken Latin.