What does Daniel 1:1 mean?

According to history, Nebuchadnezzar orchestrated three sieges against Jerusalem. They occurred in 605 BC, 597 BC, and 586 BC. After defeating the Egyptians at Cachemish in 605 BC, his father Nabopolassar was king of Babylon, but after Nabopolassar's death, Nebuchadnezzar returned to Babylon to be crowned king. Second Kings 24:1 and 2 Chronicles 36:6 record Nebuchadnezzar's invasion of Jerusalem.

The reference to the assault on Jerusalem in the third year of Jehoiakim's reign seems to conflict with Jeremiah's dating of it in Jehoiakim's fourth year (Jeremiah 25:1), but both dates are accurate. Among the possible explanations is that the Jewish calendar began in the fall, while the Babylonian calendar began in the spring. The Babylonian calendar would cite Jehoiakim's fourth year as the time of Nebuchadnezzar's invasion. Daniel seems to be using the Jewish calendar in this instance.

As part of their conquest, the Babylonians will take gifted Israelite boys back to be trained as court advisors (Daniel 1:4–5). This was likely meant to help Babylon integrate the Jewish people into their empire.