Under Rehoboam, it became the second most important city of Judah. In 701 BC, during the revolt of king Hezekiah against Assyria, it was captured by Sennacherib despite determined resistance. The town was recovered by the kings of Judah, only to fall to Nebuchadnezzar in his campaign against Judah (586 BC).
During the 19th and early 20th centuries, Lachish was identified with Tell el-Hesy on the basis a cuneiform tablet found there. The tablet is a letter from an Egyptian official named Pa'pu, reporting cases of treachery involving a local kinglet, Zimreda. Excavations at Tell el-Hesy were conducted by Petrie and Bliss for the Palestine Exploration Fund during the years 1890 - 1893, and among other discoveries was the remains of what was identified as an iron blast furnace, with slag and ashes, which was dated to 1500 BC. If the theories of experts are correct, the use of the hot-air blast instead of cold air was known at an extremely early age.
More recent excavations have identified Tell ed-Duweir as Lachish beyond reasonable doubt. Excavation campaigns by J.L. Starkey recovered a number of ostraca (18 in 1935, three more in 1938) from the latest occupational level immediately before the Chaldean siege. They form the only known corpus of documents in classical Hebrew.