Thanks for the link - very interesting reading the history of the museum's architecture. This glass covered courtyard is much more recent addition as it was finished in 2000.
Designed by Foster and Partners, the Queen Elizabeth II Great Court opened in 2000.
The courtyard had been a lost space since 1857. The re-design of the Great Court meant that this hidden space could be seen again.
The design of the Great Court was loosely based on Foster's concept for the roof of the Reichstag in Berlin, Germany. A key aspect of the design was that with every step in the Great Court the vista changed and allowed the visitor a new view on their surroundings.
Work on the Great Court's magnificent glass and steel roof began in September 1999.