A timeline organizes important events by chronological order, which is another way of saying in date order or the order in which the events happened. Timelines are not primary sources, but they can be used to organize primary source material. Historians use timelines to illustrate change over time, make connections between important people and events, show a large span of time, or focus on a particular interval or stretch of years.  

Timelines bring together many elements of history: people, places, and events. Images, specific dates, and brief descriptions help you understand why elements are included on a particular timeline. Putting all of those elements in chronological order is like putting together pieces of a historical puzzle. As you examine a timeline, look for connections and changes between its various elements.