The exact date of Altenburg Castle construction is unknown, however the traditional date given is during the reign of Valentinian I or around 370. The discovery of several small coin hoards near the ruins may indicate a construction date as early as the beginning of the 4th century AD.
The castle was built on a point above the Aar river as part of the Limes Germanicus to protect an easily fordable stretch of the river. The walls were 3–5 m thick and protected by six or eight half-round towers. Nothing is known about the number, location or purposes of the interior buildings.
The Schlössli was built in the ruins of the Roman castle during the late 10th century, probably for an ancestor of the famous Habsburg family. It remained the seat of that family until the construction of Habsburg Castlein the 11th century. After that time it became the seat of Habsburg bailiffs or knights. In 1397 the castle, village and the rest of the Habsburg Eigenamt were gifted to Königsfelden Monastery in Windisch.
On 16 November 1414, Emperor Sigismund called the Council of Constance to settle the Western Schism between the three popes (Benedict XIII, Gregory XII, and John XXIII), all of whom claimed legitimacy. Frederick IV of Habsburg sided with John XXIII. When John XXIII was declared an antipope, he fled the city with Frederick's help. The emperor then declared the Habsburg lands forfeited and ordered the neighboring countries to conquer those lands for the emperor. The city-state of Bern had already pledged their support of the emperor against the Habsburgs in 1414, and so they were ready to invade. Following a series of Confederation victories, in 1415 much of the Eigenamt including Altenburg was in Bernese hands. After Bern assumed control, the monastery retained most of their rights to the land and castles.
In 1528 Bern adopted the new faith of the Protestant Reformation and quickly seized and secularized all of the lands of the religious houses. Under Bernese rule, the castle remained a minor manor house tucked away in the country. During the 16th century a late Gothictower house topped with crow-stepped gables was added. In 1941 it was converted into a youth hostel, which it remains today.References:
The Kalozha church of Saints Boris and Gleb is the oldest extant structure in Hrodna. It is the only surviving monument of ancient Black Ruthenian architecture, distinguished from other Orthodox churches by prolific use of polychrome faceted stones of blue, green or red tint which could be arranged to form crosses or other figures on the wall.
The church is a cross-domed building supported by six circular pillars. The outside is articulated with projecting pilasters, which have rounded corners, as does the building itself. The ante-nave contains the choir loft, accessed by a narrow gradatory in the western wall. Two other stairs were discovered in the walls of the side apses; their purpose is not clear. The floor is lined with ceramic tiles forming decorative patterns. The interior was lined with innumerable built-in pitchers, which usually serve in Eastern Orthodox churches as resonators but in this case were scored to produce decorative effects. For this reason, the central nave has never been painted.
The church was built before 1183 and survived intact, depicted in the 1840s by Michał Kulesza, until 1853, when the south wall collapsed, due to its perilous location on the high bank of the Neman. During restoration works, some fragments of 12th-century frescoes were discovered in the apses. Remains of four other churches in the same style, decorated with pitchers and coloured stones instead of frescoes, were discovered in Hrodna and Vaŭkavysk. They all date back to the turn of the 13th century, as do remains of the first stone palace in the Old Hrodna Castle.
In 2004, the church was included in the Tentative List of UNESCO"s World Heritage Sites.