Ernstbrunn castle became the seat of the Ernstbrunn branch of the Counts of Sinzendorf in 1592. After the last Sinzendorf died in 1822, it was inherited by the Köstritz branch of the ruling princely House of Reuss of whom it remains their main family seat until today.
The castle is an elongated structure with four ascending courtyards on the northern slope of the Semmelberg above Dörfles. The medieval core castle on the northern rocky spur was continuously expanded during the Late Renaissance, Baroque, and Classicism periods with new groups of buildings. The core castle, dating from the 12th and 13th centuries and surrounding the innermost courtyard, sits on a free-standing limestone rock on three sides, which drops steeply towards the village of Dörfles. It forms an elongated octagon. The wall thickness of the outer wall is up to three meters. It is further reinforced on the southeast by the square keep. Originally, this keep had only three floors but was extended by an additional floor in the 16th/17th century.
In front of the gate is an early Baroque fountain. This fountain has a total of 16 coat of arms representations, 4 at the top of the shaft below the fountain bowl and 12 in pairs around the edge of the hexagonal basin.
The stone church of Gamla Uppsala, built over the pagan temple, dates from the early 12th century. Due to fire and renovations, the present church is only a remnant of the original cathedral.
Before the arrival of Christianity in Sweden, Gamla Uppsala was the seat of Swedish kings and a ceremonial site known all over northern Europe. The settlement was home to royal palaces, a royal burial ground, and a great pagan temple. The Uppsala temple, which was described in detail by Adam of Bremen in the 1070s, housed wooden statues of the Norse gods Odin, Thor and Freyr. A golden chain hung across its gables and the inside was richly decorated with gold. The temple had priests, who sacrificed to the gods according to the needs of the people.
The first Christian cathedral was probably built in the 11th century, but finished in the 12th century. The stone building may have been preceded by a wooden church and probably by the large pagan temple.