What is "ragtime"? A. A new way to make steel
B. A more modern type of music
C. A more modern way to clean
D. A new way to run the railroads

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.

i believe it would influence their own way of understanding things. it shall be a foundation where they can draw or start an argument.   historians are also  scientists that  have their tools of analysis and expertise to unlock a variety of difficulties such as relationships of man, origin, politics, economy, and culture. based on facts and understanding on these areas, they may shade light to extract ideas and develop options to validate a hypothesis or debunk it.