# 2264, according to the official Star Trek web site and the *Star Trek Encyclopedia* #

According to James T. Kirk's file on StarTrek.com (the official site of the franchise), he was **promoted to captain and took command of the Enterprise in 2264**. His first five-year mission ended in 2269. ([Source](http://www.startrek.com/database_article/james-t-kirk))

The above is the final word on this, but it is worth noting that this is corroborated by the *Star Trek Encyclopedia*, compiled by Michael and Denise Okuda, long-time Star Trek production designers (especially during the *TNG* era):

 - [Google Books preview of *ST Encyclopedia*](https://books.google.com/books?id=cbYf2l7gczUC&pg=PT933&lpg=PT933&dq=star+trek+encyclopedia+kirk&source=bl&ots=lGmQH4m0Ss&sig=szNm5Fa4RV2-eooNKaibcFIYpVQ&hl=en&sa=X&redir_esc=y#v=onepage&q=star%20trek%20encyclopedia%20kirk&f=false) (linked to relevant section)

As [*Discovery* is set in 2256](https://scifi.stackexchange.com/questions/170772/), it would be another 8 years before Kirk takes command of the Enterprise.