What if Otto II marries Swietoslawa of Poland not Theophanu

What if Otto II marries Swietoslawa of Poland, the OTL mother of Canute and the daughter of Dobrawa and Mieszko I not Theophanu. I heard that she was already at least a teen when Otto II started reigning, what if he marries Swietoslawa of Poland instead of Theophanu, what will happen to the Holy Roman Empire?
 
And why should he marry a daughter of some freshly baptized barbaric prince instead of princess of powerful empire? He was to become the emperor, so he needed a wife worthy of an emperor - at least from very high aristocracy, preferably royalty.
 
Top