Answer:
Your essay is good. You just need to go through and add a comma were "Even though the Rosetta Stone is in three different languages" is. Like "Even though the Rosetta Stone is in three different languages, archeologists and scholars were able to translate it and read the inscriptions in a modern understanding."
Explanation: I read it and checked. If you want to you can add spice to your words like if you said the word "knew" change it with the word "understood" just to it a pop.