The castle was built in the 11th century as one of the border castles located in the dangerous zone between the Frankish empire and Al-Andalus.
Even though we know that the hill dominated by Santa Creu castle was occupied in Iberian and Roman times, the first evidence of a building in the area is this fortification, built at the end of the 10th or beginning of the 11th century.
The building has its origins in a group of country people settling here with cabins made of clay and trunks, several common services (a tank or a number of silos) and a primitive church made of wood and mud.
During the Reconquest, the country people came down off the hill and began to establish the historical town of Calafell, while the castle was passed on to different noble families. One of these families, the Palou, built a small Gothic palace on the site. The castle was still somewhat strategically important until the 16th century, when it began to fall into decline; as a result, it was even used as a home for the poor. Subsequently, it was turned into a cemetery until a new castle was built in 1938.
The original building includes a church on the same site, which houses Romanesque wall paintings. One of Calafell castle´s most unusual features is the comunidor, a small 17th century building open on all four sides, with a pyramid hip roof. From here, the priest recited sections from the Gospels and blessed the district. He also banished the bad spirits that brought storms and witches.