Marie-Adélaïde, the eldest daughter of Grand Duke Guillaume IV of Luxembourg, became the first reigning Grand Duchess when her father abdicated in favor of her on February 25, 1912. This significant transition marked a new chapter in the Grand Duchy's history, as Marie-Adélaïde was not only the first female ruler in Luxembourg but also symbolized a shift in societal norms regarding royal succession. Her reign commenced in a period ripe with social and political transformation in Europe, as nations were grappling with the effects of rapid modernization and changing political landscapes. The abdication of her father and her accession took place during a time when Luxembourg was navigating its identity amidst larger European powers, including the influences stemming from the emerging conflicts in World War I.

Upon her ascension, Grand Duchess Marie-Adélaïde embraced her new role with a focus on social issues, demonstrating a commitment to improve the welfare of her people. She became known for her charitable works and efforts to promote education and healthcare within the Grand Duchy. Her reign was significant not only for being a landmark moment for female leadership in Luxembourg but also for her attempts to unite the citizens during a time of upheaval. Despite facing numerous challenges, including the pressures of two World Wars, her dedication to the people marked her tenure with compassion and resilience, which would leave a lasting legacy in the Grand Duchy.

However, Marie-Adélaïde's reign was not without its difficulties. As the world moved closer to conflict, her political decisions and alliances were scrutinized. She sought to remain neutral and preserve Luxembourg's sovereignty, but the looming clouds of World War I posed overwhelming challenges. After her eventual abdication in 1919, Marie-Adélaïde's contributions to Luxembourg continued to be acknowledged, shaping the future of its monarchy and its approach to governance.