There is little evidence for when Zenos lived, but it appears to me that he is writing at a time when the temple in Jerusalem had become corrupted. The time of Solomon may be a bit early for dating Zenos, because the Book of Mormon tells us that all prophets knew of the prophecies that Zenos taught, and Isaiah made similar prophecies in the eighth century BC, so it’s possible that Zenos and Zenock lived during that century too.
According to this prayer, Zenos had a difficult time prophesying, speaking, or preaching. He was apparently expelled. He had enemies, and he was evicted from assemblies, probably the many bodies in Jerusalem as well as local councils—rather like the poor in Antionum had been. Zenos’s contemporaries were treating him as an “enemy.” Moreover, it’s likely that some of the people who were his enemies would not have wanted his words to survive. Fortunately, a copy survived on the brass plates.
One gets the impression that one of the reasons that Zenos was cast out of the midst of the congregations was because he understood and spoke of the concept of the Son of God who was to come. He also expressed that it was because of his belief in Christ—in other words, his faith in what Alma would call the word—that Zenos’s prayers were answered.
Book of Mormon Central, “What are the Roots of Zenos’s Allegory in the Ancient World? (Jacob 5:3),” KnoWhy 70 (April 4, 2016).
David Rolph Seely and John W. Welch, “Zenos and the Texts of the Old Testament,” in The Allegory of the Olive Tree: The Olive, the Bible, and Jacob 5, ed. Stephen D. Ricks and John W. Welch, (Provo and Salt Lake City, UT: FARMS and Deseret Book, 1994), 322–346.