 John Wyclif (ca. 1330–84) was one of the most important and authoritative thinkers of the Middle Ages. His activity is set in the very crucial period of late Scholasticism, when the new ideas and doctrines there propounded accelerated the transition to the modern way of thought. On the one hand, he led a movement of opposition to the medieval Church and to some of its dogmas and institutions, and was a forerunner of the Reformation; on the other, he was also the most prominent English philosopher of the second half of the 14th century. His logical and ontological theories are, at the same time, the final result of the preceding realistic tradition of thought and the starting-point of the new forms of realism at the end of the Middle Ages, since many authors active during the last decades of the 14th and the first decades of the 15th centuries (Robert Alyngton, William Penbygull, Johannes Sharpe, William Milverley, Roger Whelpdale, John Tarteys, and Paul of Venice), were heavily influenced by his metaphysics and largely used his logical apparatus. However, his philosophical system, rigorous in its general design, contains unclear and aporetic points that his followers attempted to remove. Although an influential thinker, Wyclif pointed to the strategy the Realists at the end of the Middle Ages were to adopt, rather than fully developed it.