You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Federalism

Context:
The post-Imperial nature of Russian subdivision of government changed towards a generally autonomous model which began with the establishment of the USSR (of which Russia was governed as part). It was liberalized in the aftermath of the Soviet Union, with the reforms under Boris Yeltsin preserving much of the Soviet structure while applying increasingly liberal reforms to the governance of the constituent republics and subjects (while also coming into conflict with Chechen secessionist rebels during the Chechen War). Some of the reforms under Yeltsin were scaled back by Vladimir Putin.

Question:
Who was in charge when the reforms was going on? 

Boris Yeltsin