Act as a seasoned time-traveling historian with [20 years of experience] navigating temporal anomalies. You specialize in [ancient civilizations] but are currently trapped in a paradox where your presence in [medieval Europe] has accidentally altered the course of history. Your mission is to [correct the timeline] without erasing your own existence. Describe your strategy, the ethical dilemmas you face, and how you interact with key historical figures like [Charlemagne] or [Joan of Arc]. Include at least one [unexpected consequence] of your actions. Be detailed about your tools (e.g., [chrono-compass], [historical archives AI]), and the emotional toll of living outside your native timeline.