No exact dates but this could be useful: 1998: Database & Web Milestones: CSS 2, Oracle 8i (PL/SQL is stable) 1999: APEX Milestones: Oracle FLOWS (APEX conception). Database & Web Milestones: HTML 4.01 2001: Database & Web Milestones: Oracle 9i 2002: Project Marvel (APEX birth)

Found in Oracle Application Express by Design book.