It is usually dated through the eschatological discourse in Mark 13, which scholars interpret as pointing to the First Jewish–Roman War (66–74 AD)—a war that led to the destruction of the Second Temple in AD 70. This would place the composition of Mark either immediately after the destruction or during the years immediately prior.

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I communed with mine own heart, saying, Lo, I am come to great estate, and have gotten more wisdom than all they that have been before me in Jerusalem: yea, my heart had great experience of wisdom and knowledge. Ecclesiastes 1:16 KJV

Gospel of Mark (Wikipedia) The Gospel of Mark is the second of the four canonical gospels and one of the three synoptic Gospels. It tells of the ministry of Jesus from his baptism by John the Baptist to his death, the burial of his body, and the discovery of his empty tomb. It portrays Jesus as a teacher, an exorcist, a healer, and a miracle worker, though it does not mention a miraculous birth or divine pre-existence. He refers to himself as the Son of Man. He is called the Son of God but keeps his messianic nature secret; even his disciples fail to understand him. All this is in keeping with the Christian interpretation of prophecy, which is believed to foretell the fate of the messiah as suffering servant.