Question

Soviet leader who benefited from detente a period of relaxed tensions

Answer 1

Who was Grobesch, should be your answer.  

Answer 2

Mikhail Gorbachev, is your answer, for he opened up the USSR (or glasnot (openness)) and allowed relaxation of Communist rules and gave limited democracy to the people under USSR. However, this soon led to his usurpitation from his power. He would be remembered, however as the man who ended the Cold War.

hope this helps