Baptists have faced many controversies in their 400-year history, controversies of the level of crises. Baptist historian Walter Shurden says the word "crisis" comes from the Greek word meaning "to decide." Shurden writes that contrary to the presumed negative view of crises, some controversies that reach a crisis level may actually be "positive and highly productive." He claims that even schism, though never ideal, has often produced positive results. In his opinion crises among Baptists each have become decision-moments that shaped their future. Some controversies that have shaped Baptists include the "missions crisis", the "slavery crisis", the "landmark crisis", and the "modernist crisis".