In 1894 the United States Consul to Yucat�n, Edward Herbert Thompson purchased the Hacienda Chich�n, which included the ruins of Chichen Itza. For 30 years, Thompson explored the ancient city. His discoveries included the earliest dated carving upon a lintel in the Temple of the Initial Series and the excavation of several graves in the Ossario (High Priest�s Temple). Thompson is most famous for dredging the Cenote Sagrado (Sacred Cenote) from 1904 to 1910, where he recovered artifacts of gold, copper and carved jade, as well as the first-ever examples of what were believed to be pre-Columbian Maya cloth and wooden weapons. Thompson shipped the bulk of the artifacts to the Peabody Museum at Harvard University.
In 1913, the Carnegie Institution accepted the proposal of archaeologist Sylvanus G. Morley and committed to conduct long-term archaeological research at Chichen Itza. The Mexican Revolution and the following government instability, as well as World War I, delayed the project by a decade.
In 1923, the Mexican government awarded the Carnegie Institution a 10-year permit (later extended another 10 years) to allow U.S. archaeologists to conduct extensive excavation and restoration of Chichen Itza. Carnegie researchers excavated and restored the Temple of Warriors and the Caracol, among other major buildings. At the same time, the Mexican government excavated and restored El Castillo and the Great Ball Court.
In 1926, the Mexican government charged Edward Thompson with theft, claiming he stole the artifacts from the Cenote Sagrado and smuggled them out of the country. The government seized the Hacienda Chich�n. Thompson, who was in the United States at the time, never returned to Yucat�n. He wrote about his research and investigations of the Maya culture in a book People of the Serpent published in 1932. He died in New Jersey in 1935. In 1944 the Mexican Supreme Court ruled that Thompson had broken no laws and
