Former kitchen wing of the Chinese Palace. In 1808, the central part was reconstructed into a hospital, which existed until 1842. It was named the Court Wing, and later the Cavalry Wing, since in the second half of the 19th century it housed apartments for palace servants.

The Cavalry Wing is rectangular in plan with three elongated wings forming the shape of the letter "Ш" (Sh). The wings face the service yard, while the main facade of the main building faces the Soykinskaya road. It is two stories high. Its architectural appearance is characterized by simple clear forms, slight wall articulation, and rectangular window openings. The building became two-storied as early as 1807. At that time, its interiors were also redesigned. Slightly later, a wing was built along the central axis of the building. In 1843-1845, a major reconstruction of the palace facade was carried out.

The Cavalry Wing, located near the Chinese Palace and separated from it by an alley, was built in 1767 by architect Antonio Rinaldi. It was erected almost simultaneously with the Chinese Palace itself. Being a palace utility annex, the wing does not feature artistic refinements and has a rather modest appearance. The rectangular building with two annex wings was originally one-story and housed the kitchen and rooms for Catherine’s entourage. Due to its modest utilitarian purpose, the Cavalry Wing was placed outside the boundaries of Catherine the Great’s Private Dacha and located on the outer side of its border.

Later, in 1807, a second floor was added—with rooms that housed the ladies-in-waiting of Princess Elena Pavlovna and other palace servants. It was then that the building received the name "Cavalry Wing." In the mid-19th century, the wing underwent another reconstruction—the central segment was added. Thus, the elongated building along the border of the Private Dacha acquired a shape resembling the letter "Ш" (Sh).

Like other pavilions of Oranienbaum, the Cavalry Wing served various purposes and at different times belonged to a military hospital, a forestry technical school, and the Naval forces.

Sources:

https://peterburg.center/maps/oranienbaum-kavalerskiy-korpus.html

http://www.oranienbaum.org/oranienbaum/cavalry-building/