How did Greece lose writing for 400 years and get it back?

Writing in Greece depended on palaces, and when the palaces fell, writing went with them; it came back centuries later in a new form, an alphabet borrowed from the Phoenicians. Around 1200 BC the Mycenaean palaces that ran Bronze Age Greece began to collapse, their cities destroyed or abandoned. Linear B, the script their officials used to write Greek, had existed mainly to keep the records of the palace economy; once that economy crashed, there was nothing left to record, and on the Greek mainland the script ceased to be used. The stretch that followed, roughly 1180 to 800 BC, is called the Greek Dark Ages.

Settlements grew fewer and smaller, which suggests famine and depopulation, and most of what we know about these centuries comes from graves and the objects buried in them. It wasn't total isolation, though. Excavations at Lefkandi, on the island of Euboea, uncovered a monumental building and cemetery linked to Cyprus, Egypt and the Levant, showing that some communities stayed wealthier and better connected than once thought.

Writing did return. According to historian Thomas R. Martin, between about 950 and 750 BC the Greeks relearned how to write, not by reviving Linear B but by adapting the Phoenician alphabet, with one fundamental innovation: vowels written as letters. That Greek alphabet eventually formed the base of the one used for English today. Soon after came the markers of a new age: the first Olympic Games in 776 BC and the composition of the Iliad and the Odyssey.