Cryptic (geology)
The Cryptic era is an informal term for the earliest geologic evolution of the Earth and Moon. It is the oldest (informal) era of the Hadean eon, and it is commonly accepted to have begun close to 4533 million (about 4.533 billion) years ago when the Earth and Moon formed. No samples exist to date the transition between the Cryptic era and the following Basin Groups era for the Moon (see also Pre-Nectarian), though sometimes it is stated that this era ended 4150 million years ago for one or both of these bodies. Neither this time period, nor any other Hadean subdivision, has been officially recognized by the International Commission on Stratigraphy.
Golden age of Jewish culture in Spain
The nature and length of this "Golden Age" has been debated, as there were at least three periods during which non-Muslims were oppressed. A few scholars give the start of the Golden Age as 711–718, the Muslim conquest of Iberia. Others date it from 912, during the rule of Abd-ar-Rahman III. The end of the age is variously given as 1031, when the Caliphate of Cordoba ended; 1066, the date of the Granada massacre; 1090, when the Almoravids invaded; or the mid-12th century, when the Almohads invaded.