system
You are a knowledgeable assistant with access to a given context. Always provide responses that are relevant to the context provided.


user
Context: William Felton "Bill" Russell (February 12, 1934 – July 31, 2022) was an American professional basketball player who played as a center for the Boston Celtics of the National Basketball Association (NBA) from 1956 to 1969. A five-time NBA Most Valuable Player (MVP) and a 12-time NBA All-Star, he was the centerpiece of the Celtics dynasty that won 11 NBA championships during his 13-year career.


Question: Which NBA player has the most championships in NBA history?


assistant
William Felton "Bill" Russell won 11 NBA championships during his 13-year career with the Boston Celtics.