At a sea reef a nobleman from Trogir Koriolan Cipico, writer, humanist, military leader in the battle of Lepanto had his mansion built in 1476. Later it got its present name Kaštel Stari (the old castle). He built the mansion which was a combination of fortress and palace. It was connected to the mainland by a drawbridge (brvno). This is the reason why areas in front of the castles are named Brce (brvce). After fire in 1493 it was renovated in the Renaissance style with arcaded yard and the southern balcony decorated by the family coat of arms.
Residents of Radun, a village on slopes of Kozjak build their houses around the castle. Perimeters of the village are visible even today. Streets of the village have a rectangular pattern which could be seen in the ground plans from 1704. There is the church of St. Josip inside the village built in the 17th century by Celije Čipiko.
The parish church of St. Ivan Krstitelj (St. John the Baptist) was consecrated in 1641 and renewed in 1714. The interior is decorated with five marble altars and five altar covers. The miraculous icon of Gospa od Milosti (Our Lady of Mercy) and body of St. Felicije patron saint of the village are kept in the church.
The palace of Celio Cega family, built in the18th century is to the west from the church. Foundations of the Andreis castle could be seen on the seafloor lttle more to the west.
The new parish church is particular because its building lasted from 1871 to 1970.
Marked mountain path leads from Kaštel Stari to the Malačka saddle (480 m) where mountain houses Malačka and Split are located. These houses are starting points for mountaineering paths through Kozjak and Kaštela Hinterland. This is the easiest accessible lookout with magnificent view on Velo and Malo Kaštela Field, the bay, Split, Marjan, Trogir and Central Dalmatian islands.
A chapel with cross was built to the west at the nearby peak in memory of men of Kaštela killed in the Homeland War.
The old Croatian church of St. Juraj od Raduna (St. George) from 9th /10th century witness about existence of Radun, a village on slopes of Kozjak. The church is preserved in its original shape.
One-nave space is decorated by shallow niches. Niches divide outer wall of the rectangle apse. Archeological surveys of surrounding graves proved continuity of burials from the 9th – 15th century. Old Croatian jewelry and artifacts found in those graves are kept in the Museum of the Town of Kaštela.