The iconostasis is the most significant object in an Orthodox Church. Iconostases can be made of various materials, such as wood, marble or metal. Icons of various sizes, set out in established patterns, adorn the iconostasis. Architecturally speaking, the iconostasis is a wall. Its ecclesiastical function is to separate the naos from the chancel. Three doors lead behind the iconostasis and allow priests access into the chancel, where the altar stands.

The iconostasis

The iconography of the iconostasis developed between the 9^th and the 16^th centuries. The system of symbolic representation summarizes the central biblical stories.

The Probota iconostasis dates from the middle of the 19^th century and is painted in neo-classical style. It is composed of 36 icons divided into five registers; a register being a layer. These icons include the icons affixed to the crucifix, on the deacon’s doors and the Imperial doors. Carved and gilded decorative elements in late baroque style were designed between and around the icons. The surface of the iconostasis measures nearly 50 m².

The plan of the iconostasis with code numbers

Four circular icons and three doors make up the the inferior register A, or lowest set of images. They depict: Jesus’ sermon on the Mountain (A1), Elizabeth receiving the Virgin Mary (A3), The Good Shepherd (A6) and a scene from the life of Saint Nicholas (A8).

The Good Shepherd icon from the iconostasis

In the centre of this register are the Imperial doors, ornamented, gilded and decorated with two oval icons representing the scene of the Annunciation: the Virgin Mary praying (A4) and the Archangel Gabriel flying on a cloud (A5). The Imperial doors seem more recent than the rest of the iconostasis judging from their style, pigments and method of execution. On both sides are the deacon’s doors with archangel Michael on the left and the archangel Gabriel on the right.

The Imperial Doors

The register B is made up of four large rectangular icons, called the Imperial icons. The first icon represents Saint John the Baptist (B1), then the Virgin Mary with the Jesus Child (B2), Jesus blessing (B3) and Saint Nicholas, the patron saint of the church (B4). The register C consists of six bilobate icons representing the festive days, instead of the usual 12, and a large oval icon in the centre. First to the left is the Annunciation (C1), then the birth of Jesus (C2), the baptism of Jesus (C3), the Resurrection (C5), the Ascension (C6) and Pentecost (C7). The central icon represents the Last Supper (C4).

The Last Supper

The registers D and E are each made up of seven icons situated on two levels and, atypically, set in the form of an arch. The icons of register D are rectangular with a rounded upper part. The icons of register E are oval, except for the central one, which is round.

On level D, six of the icons represent the 12 Apostles, grouped into pairs. Starting from the left, Apostles Jacob and Thomas (D1); Mark and Andrew (D2); Peter and John (D3), Matthew and Paul (D5); Luke and Bartholomew (D6); Philip and Simon (D7). The central icon, larger than the others, represents the scene of Deisis, Jesus with the Virgin Mary on the right and Saint John the Baptist on the left (D4).

Apostles Luke and Bartholomew

The oval icons on the level E represent the 12 prophets, also grouped in pairs. Starting from the left, Prophets Zachary and Jacob (E1), Avacuum and Isaiah (E2); Moses and David (E3); Solomon and Aaron (E5); Jeremiah and Daniel (E6) and Prophets Ghedeon and Jezechiel (E7). In the middle is the Virgin Mary (E4).

Prophets Jeremiah and Daniel

A painted crucifix (F2) surmounts the iconostasis. Two vertical icons flank the crucifix: Virgin Mary on the left (F1), and Saint John the Evangelist on the right (F3). A curved wooden edge, decorated with gilded grapes and vine leaves tops the iconostasis (G).

The painter, or painters, of the icons in the Church of St. Nicholas created them using the oil technique. The paints applied were oil paints made from pigments suspended in flax oil. The wood "canvas" came principally from the linden tree. To cure it against warping, the wood was boiled in flax oil. The surface was smoothed over with a layer of ground gypsum and glue, probably made of boiled bones.

When the artist had finished painting, and adding gold leaf, the entire icon was sealed with a mixture of colophony (a resin from Asia Minor), shellac and more boiled flax oil. Most of the icons are also reinforced on the back side with two wedges.

An icon of Jesus Christ from the 19th century

Both the pronaos and the burial chamber had large and unmatched collections of icons on the eastern walls around their entrances. (This eastern orientation symbolizes resurrection. Churches are also built on an east-west axis.) The icons from the burial chamber were dismounted between 1959 and 1961 and stored in the gate tower of the fortified wall. In 1995, the iconostasis from the pronaos was moved to the Princely House to allow for excavation.

An icon of the Virgin with Elizabeth from the 19th century

The icons come from different periods, ranging from the 17^th and 19^th centuries to the 20^th. Historians surmise that a part of them was salvaged from the previous iconostasis which Prince Vasile Lupu presented in 1646 when he rebuilt parts of the monastery. They were painted using different techniques, both tempera and oil. Some icons have decorative frames of different styles and others do not have frames at all.

An icon of the Archangel Michael from 1904

The pronaos had 21 icons, including a long strip of 13 icons in a unique frame. In the burial chamber there were a total of 34 icons.

The November 1996 survey discovered wood-boring insects infesting the main iconostasis in the naos. Treatment was urgently needed. Older damage was also found. When the new iconostasis was erected its position was changed. In the new place its support structure had damaged the mural paintings on the northern and southern walls of the naos.

To find infestation restorers looked for the exit holes of wood-boring insects, crumbling and powdering. Despite evidence elsewhere, the wood of the 36 icons belonging to the main iconostasis seemed in relatively good condition. The icons which have an integral gilded frame, having been cut from the same wood, tended to suffer heavy attack on the frame in particular.

Most decorative parts, such as the columns and the floral elements, are in a fair condition and still strong enough to be reused. Many of the structural and support parts are in very bad condition, especially the lower parts, set on the floor, and the sides which touched the walls. These areas exhibited signs of wood rot. Fungi and insects also attacked the lower parts of the doors.

Contact with moisture explains the condition of these areas. The moisture condensing on the colder walls of the church contributed to the rotting of the iconostasis structure. Rising damp, moisture drawn up into the porous mortar and sandstone of the church walls, effected the iconostasis up to a height of three metres.

In April 1997, the iconostasis was taken down and the documented pieces were transported to Suceava for a pest-control treatment. Samples from the iconostasis were taken by TABOR (Metropolitan Centre of Research in Iasi), and chemical, microbiological and stratigraphical analyses performed.

After consultations between the Netherlands Institute for Cultural Heritage (NICH), and the Commission of Historical Monuments, treatment commenced. Delicate icons were subjected to a non-toxic low oxygen treatment. The structural parts of the iconostasis were subjected to gamma radiation.

Before starting the treatment, a fact sheet was filled out for each icon. This described the object, its condition, and included photographs. When needed, Japanese paper and synthetic glue protected the icon's fragile layer of paint. This application consolidates the paint layer to stop inadvertant peeling.

Consolidation of icons with Japanese paper and synthetic glue

Japanese paper is a soft tissue-like paper which is acid-free. A reversible glue, methyl cellulose, binds the paper to the icon's surface. Restorers also use Japanese paper to clean icons and murals. Cleaning chemicals are applied through the paper which acts as a buffer and absorbs the dirt. Afterwards, restorers peel the Japanese paper away. These poultices do not stay on very long, perhaps 15-20 minutes.

A damaged icon from the 17th century

Like the frame of the iconostasis, the icons - including those from the pronaos and the burial chamber - suffered from insect attack in addition to paint loss. The pests could not be poisoned outright. Common agents such as methyl bromide, phosphine, and ethylene oxide change the colour of pigments.

Considering the possible negative effects of toxic fumigation and radiation treatment on the objects, all the icons and objects with figurative paintings were treated with the low oxygen method. This strategy kills insects by robbing them of oxygen.

The objects were sealed in airtight bags along with sachets of chemicals which absorb oxygen. Then the bags were flushed with nitrogen. Nitrogen was added until the oxygen concentration in the bag reached 2-5%. Then the sealed objects were placed horizontally in the storage room at a temperature of 20-23 ºC. Under these conditions, the treatment took six weeks and killed all insects.

An icon during the low-oxygen pest-control treatment, the measuring of oxygen

The storage of icons during the treatment

Ridding the beams, struts and unpainted decorative elements of the iconostasis of wood borers proved more difficult. Even when irradiated with an iridium source (192 Ir) producing gamma energy at .67 MeV, the bugs did not die. Restorers then opted for simpler radiation: solar radiation.

Wrapped in black polyethylene sheets, parts of the iconostasis were left in the sun. Temperatures inside the black bags soon reached 55-60 degrees Celsius. The wood boring insects died within hours of heat exhaustion.

Because heating forces moisture out of the wood, and then forms condensation inside the plastic, painted objects cannot endure this treatment. Pigments would begin to detach. For structural components, however, this method of solarisation proved an effective and safe form of pest control.

Different solarisation designs