Agia Triada is located in Filellinon street and dated with relative accuracy of incisions in the second wall. The oldest mentions the year 1031, while another informs that the first that built the temple Stephen died in 1044.
The church therefore little to be built before 1031. It was the Catholic monastery that was destroyed by an earthquake in 1701. In 1780 demolished the surrounding buildings by Ali Haseki to build the precinct of the city. Ruined in 1847 bought the Russians, who repaired it in 1855, causing several changes and put new steeple.
Today it is still used as a parish of the Russian community here. The temple has been built on a larger scale than the other Athenian temples and belongs to the octagonal type. The large dome gives the interior a feeling of space unity and greatness. Outside is very attentive cloisonné with many kufic jewelry at vertical joints and only a low frieze on the east and north sides.