The Winograd Schema Challenge -- a set of twin sentences involving pronoun reference disambiguation that seem to require the use of commonsense knowledge -- was proposed by Hector Levesque in 2011. By 2019, a number of AI systems, based on large pre-trained transformer-based language models and fine-tuned on these kinds of problems, achieved better than 90% accuracy. In this paper, we review the history of the Winograd Schema Challenge and assess its significance.