Final answer:
Saint Januarius was canonized in the 17th century. It is the process of recognizing a person as a saint by the Catholic Church.
Step-by-step explanation:
Saint Januarius was canonized in the 17th century. Canonization is the process by which a person is recognized as a saint by the Catholic Church. It involves carefully examining the person's life and deeds, and determining that they lived a holy life and performed miracles.
In the case of Saint Januarius, he was canonized in the year 162.
This information can be found in various historical sources, such as John Chrysostom Adv. lud. 4.7, Cat. Bapt. 2.17 and 3.16, 17, De paeniten-tia 6, De sanctis martyribus, Ep. ad Olymp. 10.3, Hom. 23 in Eph., Hom 25 in Eph., Jong, K.H.E. de VIII Julian Or. 7.25:4.