In 1793 Brenna designed Connetable Square, modelled after Château de Chantilly. In 1796 Paul launched construction of a military base for his trusted "Gatchina troops"; the project, led by Brenna, also employed Bazhenov, Ivan Starov, Andreyan Zakharov and Nikolay Lvov, architect of the Priory Palace. At about the same time Brenna expanded the palace itself, completing two square side wings of the palace. According to Lanceray's studies of archived architectural drawings, initially Paul instructed Brenna to design these wings as single-story buildings, then two storey, and finally three storey, level with Rinaldi's central core. Archive evidence does not allow reliable attribution of other Gatchina buildings to Brenna; after Paul's ascension he retained overall management over Gatchina project, but spent most time working on Saint Michael's Castle.