Strong Support Ekaterina Dolgorukova gets only 2 Google hits in English both of which are for this article Catherine Dolgoruki on the other hand gets nearly 200 I conclude that Catherine Dolgoruki is therefore the conventional English name and naming conventions dictate that the English name should be used when it is the most commonly used name in English On the other hand there is essentially no evidence at all whatsoever that Ekaterina Dolgorukova is used at all in English