If you read through the early chapters of Genesis, you find a chronology of the patriarchs of the Bible. The chronology or genealogy gives the age at which the patriarch became a father and the name of at least his first child. The age at death is also given. Based on this we can determine what year of history in which the person was born and died.
As an example, Adam became a father at 130 years of age. His son's name was Seth. Seth became a father at age 105 years. His son's name was Enosh (not Enoch). If we assume that Adam was "born" at year zero, the Seth was born in year 130 and Enosh was born in year 235.
Because we can calculate the year of the birth of the patriarchs and we know their age when they died, we can also determine the year of history in which they died. The long lives of the patriarchs cause some interesting overlaps of life spans. For instance, Adam died in year 930 and Noah was born in year 950. There are seven patriarchs and many unnamed people who were contemporaries of both Adam and Noah. This means that Noah probably heard the story of Creation from someone who heard it from Adam.
Although Methuselah is known to have been the oldest person in the Bible at 969 years, as noted before Adam lived 930 years. Noah lived 950 years. According to Jewish tradition, Methuselah died one week before the great Flood. The name Methuselah means "when he is gone, it will happen". None of the patriarchs listed in Genesis died in the Flood. Methuselah came the closest.
In medieval times people could remember entire histories. This is probably because their minds were not cluttered with social security numbers, phone numbers, personal identification numbers, passwords, baseballs scores, television schedules and on and on. Whether or not you subscribe to the idea of an oral or written history being passed down from Adam to the children of Israel does not matter. We are told that the Lord dictated the first five books of the Bible to Moses. In fact, the Jews say that the Lord dictated to Moses letter by letter.
Adam was born about 2000 years before Abraham, who was born about 2000 years before Jesus, who was born about 2000 years ago. When you get back and look at history from an overall perspective, it does not seem that long ago that Adam walked the earth. It certainly makes the vapor of our lives seem inconsequential. But the Lord, who knows the number of hairs on our heads, cares for us and has a plan for us. If your name is written in the Book of Life, He has prepared a place for you in Heaven. Praise His Name!