Good question. My thought is similar to yours, but there is a lot of room for debate on what to send. They probably don't care about the roman empire like we do

Good question. My thought is similar to yours, but there is a lot of room for debate on what to send. They probably don't care about the roman empire like we do - but there are enough references in modern science that we need to send a summary just so they understand some things. We produce a lot of data, but most of it isn't meaningful. if this is a real situation I wouldn't be asked. So use salt