Book: Friends or enemies?

Since the reign of Peter the Great, foreign scientists, military, diplomats, artists faithfully served the Russian monarchy. There were many immigrants from Germany among them. Their descendants settled in Russia, preserving the language and some traditions that underwent changes over time in the Russian manner, and as a result became often even more Russian than the indigenous people. What can I say, it came to the point that the Russian autocrats could rightly be called Germans. The establishment of family ties between the dynasties began with the marriage of the parents of Peter III - Tsarevna Anna Petrovna and Duke of Holstein-Gottorp Karl Friedrich. After that, the process became irreversible, and two centuries later the Romanovs already had a dominant percentage of German blood.