The “Human Galaxy” Period 2 million to 100,000 years before present. Ancient humans appear to have colonized the entire galaxy. Their technology appears to have been highly advanced.
Dark Ages 100,000 to 5000 years before present. Following a poorly understood galaxy wide cataclysm or conflict, human cultures collapsed. Waves of alien incursion begin, and much knowledge is lost.
10,000 – 1,000 ybp Space Crusades. Resurgent human cultures aggressively taking back space from aliens (Space Pizarro).
Rennaissance 5000 years before, to present. Advanced human cultures emerge in Prime Space. They hold their own against outside invasion, and form powerful unions and empires. Science and culture flourish, and a drive to rediscover and resettle the galaxy begins.