Among the tasks of the historian is also that of understanding when the events he has reconstructed occurred. That is, he must put these events in order, identifying which ones happened first and which ones happened after. To carry out this task, the historian uses an imaginary line, called a TIMELINE ➡➡➡➡, on which he places the events following a CHRONOLOGICAL ORDER. That is, he arranges them in order from the oldest to the most recent. Some timelines represent VERY LONG DURATIONS ⌛⌛⌛⌛, such as that of the history of the Earth 🌍, which began billions of years ago with a great explosion called the Big Bang 💥 and which lasts until today. But there are some timelines that represent SHORTER DURATIONS ⌛, such as that of a child's life, which begins on the day of his birth 👶 and arrives, for example, until he started primary school 👦. Between the first and the last event there are many others, such as when the child started walking 🚶‍♂️, when he started attending nursery school or when he started riding his bike alone 🚴‍♂️. As you can see, thanks to the timeline it is possible to visualize the chronological order of events, identifying which ones happened before and which ones after. By comparing two timelines, such as those regarding the lives of two siblings, it is also possible to identify which events happened at the same time, that is, in the same period of time: so, for example, you can see that Virginia started walking in the same period in which her brother Guido started attending nursery school. Our timeline is made up of years, which are indicated with red ticks. In this way, we can also understand how much time has passed between one event and another. For example, we can say that 3 years have passed between the start of nursery school and the start of primary school. However, there are also timelines made up of hours 🕐, days 📆 or months 📅, which respectively represent the duration of a day, a week or a year. It is important to know that each event has its DURATION. And duration means the amount of time in which an event takes place. We have already seen that, to measure the duration of an event, you can indicate short intervals, such as hours, days and months, and slightly longer intervals, such as the years that mark the life of a child, each of which is made up of 365 days. But to measure the duration of an event you can also use much longer intervals, such as decades, centuries, millennia and even eras. Remember that a decade is equal to 10 years. A century is made up of 100 years. A millennium is made up of 1000 years and an era is made up of millions of years. So, in your life, there will be events of relatively short duration, which will last only a few years, such as the time you spent in kindergarten, which lasted 3 years. But when you study history you will realize that there will be events that are much much longer, such as some wars, which even lasted more than a century. Not to mention events that lasted millions of years, such as the presence of dinosaurs on Earth for almost the entire Mesozoic era 🦖🦖🦖. You should know that historians, in order to record events on the timeline, had to establish from which moment to start counting the years. And they chose the birth of Christ 😇 as a reference point and made it ideally coincide with the year zero. So, the years before this event are indicated with the acronym BC, which means before Christ, and are counted in a regressive sense, that is, backwards. While the years after the birth of Christ are indicated with the acronym d. C., which means after Christ and is counted progressively, that is, forward. Let's take an example: taking the year zero as a reference, coinciding with the birth of Christ, we can say that the foundation of the city of Rome occurred in 753 BC, that is, 753 years before the birth of Christ. The discovery of America, on the other hand, occurred in 1492 AD, that is, 1492 years after the birth of Christ. Is everything clear, guys? When you study history, always use the timeline. You will better understand the chronological order of events. Bye and...see you next video! 🎂🍰 Follow us on Facebook too! / pasticciotti.it Music: https://www.bensound.com