Encountered turbulent start of Russian nation (3,4)
I believe the answer is:
ran into
'encountered' is the definition.
('run into' can be a synonym of 'encounter')
'turbulent start of russian nation' is the wordplay.
'turbulent' indicates anagramming the letters.
'start of' suggests taking the first letters.
The first letter of 'russian' is 'r'.
'r'+'nation'='rnation'
'rnation' anagrammed gives 'RAN INTO'.
(Other definitions for ran into that I've seen before include "Met - in a collision?" , "Came across" , "Encountered" , "saw by accident" .)