You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Athanasius_of_Alexandria

Context:
Saint Athanasius of Alexandria (/ˌæθəˈneɪʃəs/; Greek: Ἀθανάσιος Ἀλεξανδρείας, Athanásios Alexandrías; c. 296–298 – 2 May 373), also called Athanasius the Great, Athanasius the Confessor or, primarily in the Coptic Orthodox Church, Athanasius the Apostolic, was the twentieth bishop of Alexandria (as Athanasius I). His episcopate lasted 45 years (c. 8 June 328 – 2 May 373), of which over 17 were spent in five exiles ordered by four different Roman emperors. Athanasius is a renowned Christian theologian, a Church Father, the chief defender of Trinitarianism against Arianism, and a noted Egyptian leader of the fourth century.

Question:
Who was the twentieth bishop of Alexandria?

Saint Athanasius of Alexandria