The small byzantine church of Saint Nicholas "Maroulenas" is a fine example of the single-nave cross-vaulted (or traverse-vault) architectural type, dated in 13th century. It is located in the village of Kastania, in the messinian Mani, the south-western part of Messinia region, in the Peloponnese, southern Greece. Numerous churches of byzantine to post byzantine times are preserved within the village, marking it as a particular regional religious center. "Maroulena" is believed to have been the name of the female resident who lived nearby the church and took care of it. Despite its limited size and humble aspirations, the church is decorated by fine murals, dated in the end of the 13th century. The iconographic program includes the depiction of Theotokos in the apse, scenes from the Life of Saint Nicholas and of Christ Passion, saint figures etc. Both in style and iconography, conservatism and copying western trends are to be noticed. The church was purposed to function most probably for private (a family) or limited number of faithful (the members of the quarter) gatherings. It remained in use officially till the conquest of the Peloponnese by the Ottomans, in 1460. In the 18th century, an era of local economic development, the church restored its religious function and was redecorated by few new murals. Today, it is considered a monument of byzantine art, celebating only in the Feast day of the patron saint, i.e. Saint Nicholas.