Helfenburk is a castle ruin 5.5 kilometres (3.4 mi) from the town of Bavorov in the South Bohemian Region of the Czech Republic. It is situated on Malošín stone hill at an altitude of 683 metres (2,241 ft). Between the municipalities of Koječín and Štětín there is a paved road that leads to the castle.

In 1355, a town was built by members of the Rožemberk family to defend the nearby town of Bavorov. There were four brothers – Peter, Jošt, Oldřich and Jan of Rožemberk. Building permission was given by King Charles IV. It was a reward for their services, due to them having accompanied the King on his journey to the coronation in Rome. In the year 1381, Bavorov was given the rights of a free town. After the death of Jan in 1389 and his brother Oldřich, Jan's son Jindřich III of Rožemberk became the owner of the castle. He was one of the opponents of King Václav IV. The King was trying to harm him as much as he could, allegedly even with help of Jan Žižka.

After Jindřich III's death, Oldřich II of Rožemberk, son of Oldřich, became the owner of the castle. He was very young and was tutored by Čeněk from Vartemberk. He later converted to Catholicism and was raised in this religion. After the defeat of the Hussites in Tábor, he ordered the arrest of Hussite priests in all of his lands, and imprisoned them in his castles. It is proved that at Helfenburk two Hussite priests died. After the death of Oldřich II, the ruler of the castle was his son Jindřich IV of Rožemberk, and after him Jan II. Both constantly had problems with money and debts, which had been incurred by their father's war costs. The castle was given as a guarantee to Přeškov from Čestice. The contract allowed free access to the castles by former owners. After his death the castle was bought out and returned to the Rožemberk family. The period from 1468 to 1472 was troublesome around the castle. There were neighbourly disputes between Rožemberk and the towns of Písek, Sušice and Vodňany. The castle did not face such big losses, but these disputes also affected neighbouring villages. After the death Jan of Rožemberk and subsequent death of his son Jindrich V, ownership of the castle went to Vok II of Rožemberk. Because of dues he sold the castle to the brothers Václav and Zikmund Vlček of Čenov.

Václav Vlček was originally just a regular captain, he had fought in Hungary and Poland, and in service of the King gained many military skills and became a field captain. He was known as an exceptional leader and specialist in defence. He strengthened the defence of the castle, and built three circular walls with placers for shooters between 1473 and 1483. He was very strong and unpopular with Rožemberk's neighbours, so he lent money to Count Jindřich Preuschenek of Hardegg to buy the castle, which he did in 1489. After his death, the castle returned to the hands of the Rožemberks. In 1523 there was a dispute over succession, because Petar IV. of Rožemberk, as well as his brothers, had no children. Between 1515 and 1518 the castle was in the hands of Želízko of Tourov, who fired all the staff and was all alone in the castle.