Russian names are made up of a first name, a patronymic, and a last name.
I haven't yet been able to find a good source for names, and in the 
_Novgorod Chronicle_, men are normally identified by a single name.

Patronymics consist of a father's name with "-ovich" (or, during this
period, "-ovits") or "-ova" appended, normally, depending on whether the 
child is male or female.

A sampling of Novgorod names from the late twelfth and early thirteenth 
centuries (all male), taken from the _Chronicle_:

Andrey
Anton
Arkady
Alexander
Alexey
Boris
Damyan
Danilo
Danislav
Dionisi
Dmitri
Georgi
Gyurgi
Herman
Ioan
Ivanko
Izyaslav
Konstantin
Lazor
Mikhail
Mikhalko
Mitrofan
Moislav
Mstislav
Ovstrat
Peter
Rostislav
Rurik
Simyun
Sudimir
Svyatoslav
Tverdislav
Vasily
Volodomir
Vsevolod
Yakim
Yuri
Zakhary
Zavid

As you can see, the names are pretty varied, and not all that much different
from the modern Russian names.