Esther Fahmy Wissa, Egyptian Christian nationalist, was a threat to British diplomatic interests in the eventful year of 1935. Miles W. Lampson, the High Commissioner of Egypt at the time, complained to British Secretary Robert Vansittart of her persistent efforts to unilaterally mitigate the rise of fascism in Europe. On the eve of World War II, she utilized her longstanding diplomatic relationship with the British Foreign Office to garner political support for convincing Hitler and Mussolini to cease their imperial expansions. Correspondence between the High Commissioner in Cairo and British officials in London reveal a disdain for Wissa’s idealistic plans. Yet the letters also show a marked effort to appease her in hopes of preventing any international escalations or worse—a critique of continued British colonial control in Egypt. While Lampson believed that her “peace crusade” would ultimately fail, he endeavored to demonstrate the extent of his preventative interventions: “As you see, I have done my best to pour cold water on her scheme but I am clearly not in a position to stop her.” This presentation considers the prominent international role and diplomatic interventions of Egyptian nationalist Esther Fahmy Wissa during the early twentieth century. While Wissa became an important political liaison between Egypt and the United Kingdom into the 1930s, her bold advocacy platform drew from her family’s involvement in Coptic communal politics at the turn of the twentieth century and her role in Egypt’s women’s movement following the Revolution of 1919. Extant scholarship provides limited references to Wissa’s significance who is often overshadowed by other prominent Egyptian women like Huda Sha‘rawi and Safiyya Zaghloul. Due to her influential role in both national movements and international affairs, an examination of Wissa’s impact based on her extensive imprint on the archival record is long overdue. Probing Arabic, French, and English primary source materials, this paper traces how Wissa fused Christian, national, and transnational solidarities to challenge the political status quo of her time.