In his days - i. e., 605 B.C., which was the third completed Daniel 1:1, and fourth commencing Jeremiah 25:1, year of Jehoiakim.
Nebuchadnezzar - or Nebuchadrezzar, which is closer to the original, Nabu-kudurri-uzur. This name, like most Babylonian names, is made up of three elements, Nebo, the well-known god Isaiah 46:1, kudur, of doubtful signification (perhaps “crown” perhaps “landmark”), and uzur “protects.” Nebuchadnezzar, the son of Nabopolassar, and second monarch of the Babylonian empire, ascended the throne, 604 B.C., and reigned 43 years, dying 561 B.C. He married Amuhia (or Amyitis), daughter of Cyaxares, king of the Medes, and was the most celebrated of all the Babylonian sovereigns. No other pagan king occupies so much space in Scripture. He was not actual king at this time, but only Crown Prince and leader of the army under his father. As he would be surrounded with all the state and magnficence of a monarch, the Jews would naturally look upon him as actual king.
Came up - Nebuchadnezzar began his campaign by attacking and defeating Neco’s Egyptians at Carchemish Jeremiah 46:2. He then pressed forward toward the south, overran Syria, Phoenicia, and Judaea, took Jerusalem, and carried off a portion of the inhabitants as prisoners Daniel 1:1-4 : after which he proceeded southward, and had reached the borders of Egypt when he was suddenly recalled to Babylon by the death of his father.
Three years - Probably from 605 B.C. to 602 B.C. Jehoiakim rebelled because he knew Nebuchadnezzar to be engaged in important wars in some other part of Asia.