It is my understanding of history that most newspapers used to have open political biases; they were even on the take from the party bosses, and it was written

It is my understanding of history that most newspapers used to have open political biases; they were even on the take from the party bosses, and it was written into their mission statements. You knew through what lens to filter the content, and they were happy with smaller, more limited readerships. This aim for objectivity in printed reporting was a recent 20th century development.