When the castle of Starý Plzenec fell into disrepair in the first half of the 13th century, it was necessary to build a new centre of royal power for the administration of the region of Plzeň. Construction apparently began in 1353, during the rule of Charles IV, and was completed in 1361. The original name of Karlskrone (Charles' Crown) did not become commonly used in the district, and the castle gradually took the name of the hill on which it was built - Radyně. The burgraves who governed the region were based in Radyně, and by the end of the 15th century it had been acquired by the Šternberks (1496–1561), who settled at the more comfortable castle at Bechyně. Its counterpart at Radyně, which was accessible only with difficulty, started to fall into disrepair, and its fate was sealed in the first quarter of the 16th century when it was burned down. As early as 1558, record indicated that it was abandoned, and not even the affluent Černín of the Crudenice family, owners of the castle as well as the surrounding district in the 18th century, invested in repair work. The mysterious abandoned ruin had to wait until the coming of the Romantic movement in the 19th century for more interest to be shown in it. Minor repairs and alterations were however destroyed by fire in 1886. In recent years, the castle has been progressively renovated, and a permanent exhibition devoted to its history can now be seen. The tower is open to visitors of the castle, and its observation point affords wonderful views.

Radyně (též Karlskrone, Karlshut, Kugelweit) je hradní zřícenina, která stojí na buližníkovém vrchu Radyně (569 m n. m.) mezi Plzní a Starým Plzencem v západních Čechách. Královský hrad byl postaven před rokem 1361 během vlády Karla IV. Původní německé jméno Karlskrone se neujalo, a hrad byl již krátce po svém založení nazýván podle kopce na němž stojí. Hrad je přístupný veřejnosti. Hrad během staletí mnohokrát změnil svého majitele. V roce 1920 ho od Adolfa Arnošta z Valdštejna koupil Starý Plzenec a do roku 1928 proběhla velká oprava hradu. Počátkem 50. let 20. století se stal hrad majetkem státu a následně byl na hradní čtverhranné věži vybudován převaděč televizního signálu. V 70. letech 20. století proběhla další rozsáhlá opravu hradu a pod hradem byla vybudována restaurace s parkovištěm. Od 90. let je hrad opět majetkem města Starý Plzenec.

Distance from parking lot: 1 km. capacity - cars: 15, free; capacity - coaches: 1, free. Adults: 40 CZK - children from 6 to 15 years, students under 26 with a valid student card, holders of ZTP and seniors over 65: 30 CZK - children under 6, holders of ZTP / P + 1 escorts: free entry Free: - children under 6, holders of ZTP / P + 1 escorts

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