The history of the Slavic languages stretches over 3,000 years, from the point at which the ancestral Proto-Balto-Slavic language broke up (c. 1500 BC) into the modern-day Slavic languages. The first 2,000 years or so consist of the pre-Slavic era; a long, stable period of gradual development during which the language remained unified, with no discernible dialectal differences.