Thus far, significant quantities of x4C, x4L, and x2U stamps have been excavated from below the destruction layer caused by the Assyrian conquest of Sennacherib, but only a single specimen each of the G2T and M2D stamps (excavated from Jerusalem, which was not destroyed by Sennacherib). This suggests that 12 of the 21 seals were made prior to the attack, and the remaining 9 afterwards. The first significant evidence to support this datum came from the landmark excavations at Timnah led by George L. Kelm and Amihai Mazar.