Around the turn of the twentieth century, British metaphysics of time saw two major changes. First, from the 1870s to 1900s, philosophers became convinced time was unreal. Philosophers en masse denied the reality of time, from F. H. Bradley to J. M. E. McTaggart. Second, from the 1890s onwards, philosophers began to embrace time, developing newfangled theories. The early theories of Victoria Welby, F. C. S. Schiller, Bertrand Russell, and Samuel Alexander, conceived time to be static. The later theories of C. D. Broad, Arthur Eddington, Susan Stebbing, R. G. Collingwood, and many others, conceived time to be dynamic. This broad-brush, big ideas paper asks, Why did these two changes occur? It explores the role of biological evolution, the spatialisation of time, and temporal psychology; and asks how the debates between static and dynamic theories got started.