The history of Sindh refers to the history of the modern-day Pakistani province of Sindh, as well as neighboring regions that periodically came under its sway. Sindh was the site of one of the Cradle of civilizations, the bronze age Indus Valley civilisation that flourished from about 3000 B.C. and declined rapidly 1,000 years later, following the Indo-Aryan migrations that overran the region in waves between 1500 and 500 B.C. The migrating Indo-Aryan tribes gave rise to the Iron age vedic civilization, which lasted till 500 BC. During this era, the Vedas were composed. In 518 BC, the Achaemenid empire conquered Indus valley and established Hindush satrapy in Sindh. After Alexander the Great's invasion, Punjab became part of the Mauryan Empire. After its decline, Indo-Greeks, Indo-Scythian