Jeremiah had prophesied a period of seventy years of exile for the Israelites. It is difficult to determine just when those seventy years began and ended. Since the number seven and its derivatives denoted completeness, the seventy-year period may have been a round number representing an approximate number of years.
As has been previously noted, Daniel was living during that exilic time of Jewish history many years prior to the fulfillment of his prophecies. Recognizing the many transgressions of the Jews, he poured his heart out to God confessing those sins and fervently begging for Him in His mercy to forgive them. They had already suffered much physical and mental pain because of those transgressions.
While Daniel was praying, Gabriel appeared to him another time and informed him of a seventy weeks period after which the Messiah would come. His vision of that seventy weeks span consisted of seven weeks followed by a sixty-two weeks period and one week. Those numbers were also highly figurative in nature. It is probable that the weeks represented years. The approximate time between the return of the Jews from exile and the coming of the Messiah could have been rounded off as seven times seventy. His life and death were followed by the birth of His church and the destruction of Jerusalem and the temple.