The birth of Jesus, which we celebrate today, was prophesied centuries before the event, most notably by the prophet Isaiah. According to Wikipedia: :The oldest surviving manuscripts of Isaiah are two scrolls found among the Dead Sea Scrolls; dating from about a century before the time of Jesus, but those manuscripts have been dated to as far back as 408 B.C. There are two well known and relevant quotes from Isaiah about today.
Here's the first:
The second will be recognized from George Frideric Handel's Magnus opus, Messiah.Therefore the Lord himself will give you a sign. Behold, the virgin shall conceive and bear a son, and shall call his name Emmanuel.
Here's the quote:
For unto us a Child is born, Unto us a Son is given; And the government will be upon His shoulder. And His name will be called Wonderful, Counselor, Mighty God, Everlasting Father, Prince of Peace.