Discovery of the Monolith and other xeno-archeology under Europa’s ocean provides proof of non-terrestrial life, and a strange link to the horrors of Vector past. Transcendent corruption of the Orca bioprobes creates trouble through the present era.
Reference: Europa history notes, HSD 2.0
Date Notes: Estimated from colonization of Europa. The Monolith was discovered during the initial transportation of colony and supplies, a narrow window.