Conversation so far:
When did Richard Stallman attend harvard?
As a first-year student at Harvard University in fall 1970.
what did he study at harvard?
Stallman received a bachelor's degree in physics (magna cum laude) from Harvard in 1974.
did he do any research?
While working (starting in 1975) as a research assistant at MIT under Gerry Sussman.
did anything notabke happen at harvard?
Stallman considered staying on at Harvard, but instead he decided to enroll as a graduate student at MIT.

Question: when did he enroll to MIT?
Self-contained rewrite: when did Richard Stallman enroll to MIT?