Can we understand texts that are written for different audiences in different times or cultures?

I think we can understand texts that are written in different period, but I believe people have to pay a lot of time in oder to understand those texts. There are many media preserved from archaic period until know, and that's how people know the history; however the best medium I believe In order to know the history is the written form. People been doing this for a long time, to interpret the written texts but it is not a easy task in which it requires people to have research. Shakesphere's plays are written in a different period, but people, even students, are reading it. Even though people can't understand the text perfectly, they can still get the main point, stories of the plays.