Complex sentence: The jump drive was discovered on Vland in -9235 (4715 BC); immediately the Vilani discovered a number of interfertile and technologically primitive human races on worlds within 60 parsecs.
Split into simpler sentences: The jump drive was discovered on Vland in -9235 (4715 BC). Immediately the Vilani discovered a number of interfertile and technologically primitive human races on worlds within 60 parsecs.