Piper’s first general plan for the area around Old Haga is dated 1781. By blasting away hills and filling out hollows, the terrain was modelled into a gentle rolling landscape. It was at this time that the lawn was formed on the Haga property, present-day Vasaslätten. The islet parks for strolling in were improved and the canals extended. New roads were built and existing ones improved. A protecting ditch and rampart was constructed on the western border along the main road to Uppsala. The Dala Regiment was commandeered to Stockholm to accomplish this work.
The next stage in the creation of Haga Park took off when Gustav III returned home from his journey abroad in 1783-84, which had included visits to Italy and France. The stay in Europe had aroused the king’s interest in turning Haga into a great display park built around a magnificent palace. Old Haga was moved to its present location on a rise in order to give room for a small ornamental building. By purchasing the neighbouring property of Brahelund in 1785 the king’s land was extended to the north and thereby increased twofold. Now everything was in place for constructing a park on a much grander scale.
Gustav III’s pavilion was erected on Brahelund and the existing building on that site was incorporated into the structure of the pavilion. A summer palace was planned for the slopes above Brahelund which now became the main focus of the park. From here a line of sight extended all the way to the royal palace in Stockholm. Old and New Haga were linked by a road along Brunnsviken and several other footpaths were created. The foundations for the palace were laid in 1786. It was intended to be a magnificent classical temple and its architect was Lous Jean Desprez.
At the same time the great lawn that sweeps down towards Brunnsviken was constructed – perhaps the most outstanding feature of the park today. From 1787–1790 work was undertaken on the canals and artificial islets both south of Haga Palace and at Tingsslätten, north of Stallmästargården. These disappeared, however, when Brunnsviken was lowered in 1863 to enlarge the Ålkist Canal. Between 1785–1800, 26,000 trees were delivered to Haga.
The late 1780s witnessed the erection of several of the park’s exotic buildings designed by the leading architects of the day: the Turkish Pavilion (Piper), the Chinese Pavilion (Louis Jean Desprez), Gustav III’s Pavilion (Olof Tempelman, Louis Jean Masreliez), the Copper Tent (Desprez) and the Temple of the Echo(Christoffer Gjörwell).