Give me a summary of the history of Thackeray Hall at the University of Pittsburgh based on this passage.

The building is the former National Union Fire Insurance Company building built circa 1923–1925 in the Early Classical style.[4][5] The building was purchased by the university in 1968 for $1.875 million ($14.6 million in 2021 dollars[6]), and was originally purposed for faculty offices.[7] It was known as the Social Sciences Building until 1972 when it was renamed Mervis Hall and designated as the home of the Graduate School of Business.[4] In 1983, when the Graduate School of Business moved into a new building also named Mervis Hall, it was renamed Thackeray Hall.

Thackeray Hall used to be the building for the National Union Fire Insurance Company until it was purchased by the University of Pittsburgh in 1968 for $1.875 million. First, it was used for faculty offices, then later known as the Social Sciences Building until it was renamed Mervis Hall. In 1983, it was renamed Thackeray Hall and has housed the university's Department of Mathematics since then.