The former Palazzo Baldinotti Carpegna was built in the late 17th century, to a design by Giovanni Antonio de' Rossi [1619-1695] in its present location.
In the early 1900s, it housed part of Rome University, until this was relocated in 1930. Following the adoption of the city development plan in 1926, the building was demolished and later rebuilt. The new façade was torn down and rebuilt further back to make room for a wider Corso Rinascimento.

In the 1940s, when the building was connected to Palazzo Madama, more space was needed to build a wider road [Via della Dogana Vecchia] behind it. The two buildings were connected with a two-storey portico with granite columns in 14th-century style. The upper level portico has ionic columns and features large windows. The ground floor portico is open and is lined with Tuscan columns.

The triangle between the portico, Palazzo Madama, the Crescenzi Tower and the building designed by Koch is known as the Palm Garden, or Cardinal John's Garden. A fresco by Lodovico Giminiani representing the founder of the Carpegna family was detached from this building, using a very advanced technique for that age, and moved to a gallery in Palazzo Madama, renamed the Gallery of the Hero after the fresco. Senate Standing Committees meet in Palazzo Carpegna.

It was for this reason that the building was recently renovated, to make the most of its ample spaces, adopting innovative and prestigious architectural solutions which successfully combine sober elegance and state-of-the-art functionality.