The Three Hierarchs Monastery in Iași is a foundation of Prince Vasile Lupu, built between 1637-1639. It is dedicated to the Three Great Hierarchs: Basil the Great, Gregory the Theologian and John Chrysostom. The unique edifice in Romania combines traditional forms with precious materials and refined decorations, being considered the most precious church monument in Iași. It is located in the traditional center of Iași, on Ștefan cel Mare și Sfânt Boulevard (formerly Ulița Mare).

The monument broadly follows the plan of 16th-century Moldavian churches - a triconical plan influenced by the Galata church, however, having an additional spire above the narthex. The vault, respecting the ingenious Moldavian system of vault construction, comprises two superimposed registers of four and eight arched arches respectively arranged obliquely and which, together with the pendants above them, manage to reduce the diameter of the bell tower. On the outside, on the facades, the arrangement of decorative elements reminds us of the church of the Dragomirna monastery (Moldova 1606-1609) and the division of the parapet with the help of a belt found in the monasteries of Muntenia. The influence of Transylvanian Gothic is visible in many places: in the buttresses, in the stone reinforcement of the windows, in the door profile, the borders with baguettes and arches in braces.

What gives the building a particular character and places it among the most original creations of Moldavian art is the harmonious contrast between the well-relieved and proportionate architectural forms and the sculpted decorations that dress the entire surface of the four facades like a lace, including the buttresses and archivolts on the sides and at the base of the bell towers. The ornaments are of the most varied: deep niches with fasciculated arches according to oriental models, small columns like those of Russian churches, Persian vases from which flowering branches rise, geometric motifs also found in Georgia and Armenia, the facing divided by a belt in the form of a twisted rope framed by two marble strips decorated in Renaissance or Baroque style. All of this is arranged in a unit to which the light seems to give life. In addition, emphasized by a lazurite coloring highlighted by gilding, this decoration contributes fully to the fame that the Three Hierarchs church has acquired. gained since its construction. The painting was done by the most famous craftsmen: Sidov Pospeev, Iacob Gavrilov, together with the Moldavian painters Nicolae Zugravu the Elder and Stefan.

Vasile Lupu brought the relics of Saint Parascheva to Trei Ierarhi and placed them in 1641 in a marble niche, to the right of the princely throne. Thus, we have at Trei Ierarhi in Iași one of the rare models of the architectural and ornamental device that was used in the Orthodox world for the exhibition of the relics of saints.

The bell tower at the main entrance was a remarkable monument that was located about 20 meters away from the altar. On the bell tower there was a beautiful coat of arms of Moldova, with the head of an ox, the moon and the sun, as well as heraldic lions.

The refectory at Trei Ierarhi was, in the first half of the century XIX, the main building of the Vasiliene Academy. The Gothic hall in the interior is a replica of the Gothic hall in Dragomirna, and served as a model for the one in Cetățuia. In 1714, the King of Poland Stanislas Lesczinski was hosted here.

The printing house that was installed here, whose printing press was brought from Kiev, thanks to the help of Metropolitan Petru Movilă, was run by the abbot of the monastery and director of the newly opened school, the monk Sophrony. The first printed work (in Greek) from Moldova appeared here and, the following year, the famous Kazaniye of Metropolitan Varlaam.

Looted and burned by invaders from the East (1650) and from the North (1686), shaken by earthquakes in 1711, 1781, 1795, 1802) the church will be restored between 1882 - 1887 (architecture) and the painting and interior decoration lasted until 1898, the re-consecration of the place taking place in 1904. Along with the founders, at Trei Ierarhi the scholar voivode Dimitrie Cantemir (1710-1711) and the first ruler of modern Romania, Alexandru Ioan Cuza (1859-1866) sleep their eternal sleep.

After functioning for a long time exclusively as a church, in 1991 the monastery of the Three Hierarchs was re-established

In 1997, the bust of Mihai Eminescu, who lived here for a while, was unveiled within the monastery.

Today, the Trei Ierarhi monastery is almost 380 years old. It represents an unmistakable monument, which preserves all the power of tradition. The patina of time that today dulls the brilliance of the decoration of yesteryear lends it instead the sobriety of age.