There is a historical problem at the end of Daniel 5 that carries us into chapter six. Daniel says that “Darius the Mede” overcame Babylon at the age of sixty-two. The problem is compounded in 9:1 as he is further identified as the “son of Xerxes.”
If we just stick with the names, we must identify this Darius as Darius II, the grandson of Xerxes II. That gives us a date of 424 B.C. and makes Daniel nearly two hundred years old.
It’s a difficult historical issue, but one that is not without resolution.
First, the conqueror of Babylon was Cyrus, an undisputable fact. But, Cyrus was the son of a Median princess and was known even to Nabonidus as “Cyrus the Mede.” “Darius” was an old Iranian title for a king, and we know that Cyrus (or one of his descendants) made up another title, a Persian one, Xerxes, as a title for king. Second, remember that this book is not written by Daniel, but by someone who had access to Daniel’s writings. The first six chapters are written about Daniel, entirely in the third person. The second six chapters are also written about Daniel but the writer admits to reading the writings of Daniel (cf. Daniel 7:1). The book would have been composed long enough in the future that the writer would know these Persian titles. In fact, the writer admits to them. In the last verse of chapter six, he writes “So Daniel prospered during the reign of Darius, who is also [the NIV translates this “and”] Cyrus the Persian.”
What should not be overlooked in the chapter however is the great faith of Daniel and Cyrus’ acceptance and admission of the sovereignty of the God of Israel.