On his mother's side, Hayek was second cousin to the philosopher Ludwig Wittgenstein. His mother often played with Wittgenstein's sisters, and had known Ludwig well. As a result of their family relationship, Hayek became one of the first to read Wittgenstein's Tractatus Logico-Philosophicus when the book was published in its original German edition in 1921. Although Hayek met Wittgenstein on only a few occasions, Hayek said that Wittgenstein's philosophy and methods of analysis had a profound influence on his own life and thought. In his later years, Hayek recalled a discussion of philosophy with Wittgenstein, when both were officers during World War I. After Wittgenstein's death, Hayek had intended to write a biography of Wittgenstein and worked on collecting family materials; and he later assisted biographers of Wittgenstein.
What was the name of the book Wittgenstein published in 1921?
Wittgenstein's Tractatus Logico-Philosophicus

Methodism identifies principally with the theology of John Wesley—an Anglican priest and evangelist. This evangelical movement originated as a revival within the 18th-century Church of England and became a separate Church following Wesley's death. Because of vigorous missionary activity, the movement spread throughout the British Empire, the United States, and beyond, today claiming approximately 80 million adherents worldwide. Originally it appealed especially to workers, agricultural workers, and slaves.
How did the Methodist movement spread so far and wide?
vigorous missionary activity

The Late Middle Ages represented a period of upheaval in Europe. The epidemic known as the Black Death and an associated famine caused demographic catastrophe in Europe as the population plummeted. Dynastic struggles and wars of conquest kept many of the states of Europe at war for much of the period. In the Balkans, the Ottoman Empire, a Turkish state originating in Anatolia, encroached steadily on former Byzantine lands, culminating in the Fall of Constantinople in 1453.
When did the Ottoman Empire conquer Constantinople?
1453