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.
Abyssinian people
Ge'ez literature is considered to begin with the adoption of Christianity in Ethiopia and Eritrea, as well as the civilization of Axum in the 4th century BCE during the reign of Ezana. While Ge'ez today is extinct and only used for liturgical purposes in the Eritrean Orthodox Tewahedo Church and Ethiopian Orthodox Tewahedo Church, many related Ethiopian Semitic languages continue to be spoken such as Tigre, Tigrinya, Amharic, Harari, Gurage, Zay, Silte, and Argobba. Some of these languages, such as Harari and Tigre, are traditionally written in the Arabic script.