Most people imagine history as a straight line, a constant march of progress from the past into the future. But what if it isn't? Historians William Strauss and Neil Howe presented a different idea in their book, The Fourth Turning. They argue that history moves in cycles, much like the seasons of a year.

The foundation of their theory is a unit of time called a saeculum.

Think of a saeculum as history's version of a full year. Just as a year has four seasons — spring, summer, fall, and winter — a saeculum has four distinct periods. Strauss and Howe call these periods "Turnings."

Each Turning lasts about 20 to 25 years and has its own unique social mood and character. Together, the four Turnings complete the cycle of the saeculum.

The sequence is always the same. A First Turning is followed by a Second, then a Third, and finally a Fourth. After the Fourth Turning, the cycle begins anew with the start of another saeculum.

Each turning shapes the generations that live through it, and in turn, those generations shape the next turning. This creates a recurring rhythm in history, an alternating pattern of crisis and stability, of societal consensus and fragmentation.

This framework doesn't predict specific events. Instead, it offers a way to understand the mood and direction of society at any given time. It suggests that while the details of our lives change, the underlying patterns of social change are remarkably consistent over the long term.

Understanding this cycle of four turnings within a saeculum is the first step. Next, we'll explore what defines each of these historical seasons.