Most alternate history posts about Frederick III, touch on the changes that might have happened if had not died as young as he did. What I'm curious about is what might have been had he taken the throne earlier.
Let's say that in 1861, the day before Frederick William IV dies, his brother William dies. The cause of death is irrelevant save for the fact that it is not assassination, so illness, lightning strike, what have you. Frederick III and Victoria become King and Queen of Prussia. How drastically does this alter history?