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.
History of Western civilization before AD 500
The earliest urban civilizations of Europe belong to the Bronze Age Minoans of Crete and Mycenaean Greece, which ended around the 11th century BC as Greece entered the Greek Dark Ages. Ancient Greece was the civilization belonging to the period of Greek history lasting from the Archaic period of the 8th to 6th centuries BC to 146 BC and the Roman conquest of Greece after the Battle of Corinth. Classical Greece flourished during the 5th to 4th centuries BC. Under Athenian leadership, Greece successfully repelled the military threat of Persian invasion at the battles of Marathon and Thermopylae. The Athenian Golden Age ended with the defeat of Athens at the hands of Sparta in the Peloponnesian War in 404 BC.