In 1887, a collection of clay tablets in Babylonian cuneiform was discovered, containing the diplomatic archives of the Egyptian Pharaoh Akhen-aten and his father Amenhotep III, dealing with the affairs of the north (Syria, Babylon, Hittites etc). They describe the state of Palestine before the Exodus. Canaanite vassals of Egypt write asking for help against the Hittites and marauders called "Habiru", from the hill country. These are thought to be the Hebrews belonging to the army of Joshua invading the Promised Land.
The inscription on this tablet is:"Say to the king, my lord, my god, my Sun: Message of Zimreda?, your servant. I fall at the feet of the king, my lord, my god, my Sun, seven times and seven times. I have heard the orders that the king, my lord, wrote to his servant, 'Obey your commissioner, and guard the cities of the king, your lord, where you are.' I am indeed obeying the orders that the king, my lord, gave me. May the king, my lord, be informed about his servant. Consider the deed of Beya, the son of Galatu, [against] me. My men whom I sent to serve in Jaffa and to guard the granary of the king, my lord, Beya the son of Galatu has just taken. May the king, my lord, say this to me, 'Abandon your city, (fleeing) from before Beya,' then of course I will abandon it, and I will come and of course serve the king, my lord, day and night, forever."
Israel Museum Link
There are more tablets from Tel el Amarna in the British Museum in London.