This book is the author’s second published by Xlibris, the first being Defending Rome: The Masters of the Soldiers, published in 2011. It explores the consequences of two battles fought in 1453 – the fall of Constantinople to the Ottoman Turks in May and the French victory over the English two months later at Castillon in the last battle of the Hundred Years War. The book considers the impact of these events on a diverse range of topics, including military outcomes, strategic consequences, economic developments, and cultural and religious implications. It concludes by assessing the significance of these two battles in influencing the transition of Europe from the medieval to the modern age.