The design of a new structure to replace the old ruined castle of Poppelsdorf commenced in 1715 at the request of the owner, Joseph Clemens, Archbishop-Elector of Cologne, who engaged the French architect Robert de Cotte. Clemens wanted a maison de plaisance that would be near his remodeled Bonn Palace one-half mile to the north. There was to be a canal between the two, following the example of the Palace of Versailles and the Trianon de Marbre.
Work came to a halt after Clemens' death in 1723, but his nephew and heir, Archbishop of Cologne Clemens August, undertook a second campaign of construction in 1745–1746.
Under the Prussian rule, in 1818 the Palace and the nearby Park became part of the University of Bonn. In the same year the Park was converted to the Botanical Garden of Bonn, which today contains about 0.5 hectares of greenhouse area with eleven greenhouses and about 8.000 different plants.
In 1944 the Palace was heavily damaged by an Allied air attack. It has been rebuilt in a much simpler appearance from 1955 on.References:
The Temple of Portunus or Temple of Fortuna Virilis ('manly fortune') is one of the best preserved of all Roman temples. Its dedication remains unclear, as ancient sources mention several temples in this area of Rome, without saying enough to make it clear which this is.
The temple was originally built in the third or fourth century BC but was rebuilt between 120-80 BC, the rectangular building consists of a tetrastyle portico and cella, raised on a high podium reached by a flight of steps, which it retains.
The temple owes its state of preservation to its being converted for use as a church in 872 and rededicated to Santa Maria Egyziaca (Saint Mary of Egypt). Its Ionic order has been much admired, drawn and engraved and copied since the 16th century. The original coating of stucco over its tufa and travertine construction has been lost.