>>>When Christof married, he took his wife's family name. Earlier his name was Christof Lange.
>>
>>Is this a German thing?
>
>It's not unusual here in Europe, especially if the man has a very common family name. My guess is that it happens in 5-10% of all marriages.

I think much more. In most of the marriages one of the partners takes the last name of the other partner. I'd hazard to guess that 5-10% is the percentage of the cases where they keep the names as they were, or one adds the last name of the other.