The oldest of Mesta’s monuments is the church of Old Tachiarch. Before the Pammegiston Tachiarchon church was built, the village had as its main church the “Old Tachiarch”. The temple is considered to have been built in 1412. Initially it was small, arch- covered, single-aisled, but when the religious needs of the village increased it was expanded into two aisles with a uniform roof and cross vaults at its north aisle. The expanding took place in 1794.
Internally, the old section of the temple, was decorated by remarkable wall paintings which destroyed by the Turks during the massacre of Chios. Because the whole temple was in a bad shape it was renovated in 1883 by a craftsman coming from Patrika (a village of Chios). It took ten whole years to the craftsman to complete his work. It is of stunning and very special beauty the chancel screen inside the temple that is very well preserved in our days, an excellent sample of the native wood-crafting. It is decorated with embossed carvings that represent the life of the Christ from His birth until His crucifixion, and various themes from the Old Testament. On the opposite side there is a painted two- headed eagle. This gives evidence of some patriarchic privilege that had been given to the temple. The rest of the buildings around the temple are in perfect harmony with it. It seems that this building complex was a monastery with its own defensive measures.