Simplify the following text for a Grade 7 native English-speaking person.
Original: For certain periods of time between the 17th century and 1959 , the Dalai Lamas sometimes directed the Tibetan Government , which administered portions of Tibet from Lhasa . The 14th Dalai Lama remained the head of state for the Central Tibetan Administration ( `` Tibetan government in exile '' ) until his retirement on March 14 , 2011 .
Simplified: Between the 17th century and 1959 , the Dalai Lama was the head of the Tibetan government .