John Gills Exposition of the Bible Commentary - Daniel 5:31
And Darius the Median took the kingdom ,.... This was Cyaxares the son of Astyages, and uncle of Cyrus; he is called the Median, to distinguish him from another Darius the Persian, that came after, Ezra 4:5 , the same took the kingdom of Babylon from Cyrus who conquered it; he took it with his consent, being the senior prince and his uncle. Darius reigned not long, but two years; and not alone, but Cyrus with him, though he is only mentioned. Xenophon F11 Cyropaedia, l. 8. c. 36. ... read more
Matthew Henry's Complete Commentary - Daniel 5:30-31
Here is, 1. The death of the king. Reason enough he had to tremble, for he was just falling into the hands of the king of terrors, Dan. 5:30. In that night, when his heart was merry with wine, the besiegers broke into the city, aimed at the palace; there they found the king, and gave him his death's wound. He could not find any place so secret as to conceal him, or so strong as to protect him. Heathen writers speak of Cyrus's taking Babylon by surprise, with the assistance of two deserters... read more