Neu-Thierstein Castle was founded in 1100 and a new building was built around 1294/95. The castle was apparently built by the Saugern-Pfeffingen family as a seat for a Kastvogtei (or a vogt with authority over a religious structure) who ruled over Beinwil Abbey. The first mention of the castle comes from 1321 when it was called Bello. As heirs of the Saugern-Pfeffingen family, in the late 12th Century, the count of Thierstein took over the castle and the Kastvogtei post. By 1400 it was known as Thierstein Castle. The castle was occupied by the Canton of Solothurn in 1445, 1467 and 1499. After the extinction of the counts of Thierstein in 1522, Solothurn acquired the castle and made it the administrative center of the secular bailiwick of Thierstein. In 1798 the castle was sold for demolition. However, in the 19th Century, the destruction of the castle are stopped by private individuals who wanted to repair the ruins. The ruins were surveyed and archeologically investigated in 1985.
The castle ruins are on a small rocky outcrop above the municipality of Büsserach. The ruin consists of a residential tower with ancillary buildings. Traces of a bailey and the old gate house on the south side can still be seen.
References:Stobi was an ancient town of Paeonia located near Gradsko. It is considered by many to be the most famous archaeological site in North Macedonia. Stobi was built where the Erigon (Crna River) joins the Axios (Vardar), making it strategically important as a center for both trade and warfare.
Stobi developed from a Paeonian settlement established in the Archaic period. It is believed that in 217 BCE, Philip V annexed Paionia during his campaign against the Dardani who had entered Bylazora, the largest Paeonian town.
The city was first mentioned in writing by the historian Livy, in connection with a victory of Philip V of Macedon over the Dardani in 197 BC. In 168 BC, the Romans defeated Perseus and Macedonia was divided into four nominally independent republics. In 148 BC, the four areas of Macedonia were brought together in a unified Roman province. In the reign of Augustus the city grew in size and population.