Trenčín occupies a strategic position in the Váh River Valley. Situated at the crossroads of long-distance routes, the rock on which Trenčín Castle is built has been inhabited since the Palaeolithic Age. The castle rock saw also Romans who carved an inscription on it in 179 CE in memory of a victory in battle. The inscription bears reference to a winter that Romans spent in Laugaricio. The existence of a Slavic settlement here has also been documented by a quatrefoil rotunda dating from the 9th and 10th centuries which was found on the rock. Presumably it served as a princely church for castle lords according to the tradition of a Slav fortress.
The first mention of Trenčín dates from the 12th century. The oldest traces of a medieval settlement in the town were found along the access road to the castle. At the end of the 13th century the originally royal castle was acquired by the Čák family, and during the rule of oligarch Matúš Čák it became the centre of his large dominion, which included about 30 castles. The superstructure of the dominant defence tower, called Matúšova veža and originally built in the 11th century, dates back to this period. After the death of Matúš Čák the castle fell once more to the crown which added representative gothic palaces and the chapel.
The settlement below the castle, guarding the ford across the Váh River, was gradually extended and in its centre the uneven market place was formed. The access road to the castle led from this square. Burghers gained privileges in the 14th century allowing them to hold fairs. The privileges of a free royal town, including the right to store goods, to build fortifications and to exercise judicial power, were granted to the town in 1412. The town was fortified in the 15th century. Its fortifications were connected with outer walls of the castle fortification system and entry into the town was guarded by two town gates. The preserved Lower Gate (Dolná brána) dates from 1543. During this period the new owner of the castle, Štefan Zápoľský, built a new palace and strengthened the fortifications. The staircase, Farské schody, mentioned in 1541, served as fast passage for defenders to the walls in the neighbourhood of the area called Mariánska hora and to the armoury. The staircase was later used as a connection between the Main Square and Mariánska hora.
Burgher houses on the square have mostly medieval cores. The houses were enlarged after fires and in accordance with increasing needs of burghers. In the second half of the 16th century and in the 17th century houses with arcades were built around the square, however these were pulled down during the 19th and 20th centuries. The most interesting secular building below the castle is Katov dom (the Executioner’s House) on Matúšova street. The original medieval two-room house with its remarkable gallery has been renovated and now houses the exhibition ‘Law and Justice in Old Trenčín’.
Plundering of imperial troops under the command of General Katzianer and the subsequent fire in 1528 damaged the town and also the fortified Gothic Parish Church of the Nativity of the Virgin Mary standing separately on the hill known as Mariánska hora. It was then rebuilt in the Renaissance style. Near the parish church is the Chapel of St Michael with its Gothic windows and vaults built into the walls. Originally it had an ossuary in the basement. The building served as an armoury during Turkish wars and later as a granary.
The town suffered greatly during the rebellion of the estates and Ottoman expansion. The quite unique findings for Slovak conditions of the base of the outer town fortifications from the 17th century, whose remnants were found outside the boundaries of town conservation reservation, remind us of this period. This fortification belonged to an advance line of anti-Turkish fortifications. It guarded the entrance to the city through the Lower gate and southwestern suburbs. According to the preserved historical map it intersected the flat land near the south bank of the Váh River. The remnants were discovered near the former House of the army. In 1670 the owners of the castle, the Illésházy family, had to accommodate an imperial garrison which secured the defence of the castle and town and then remained in occupation for more than 100 years. The castle was destroyed by fire shortly after the garrison’s departure in 1790. Thereafter it fell into decay and was left without any maintenance till the second half of the 20th century. The present-day appearance of the castle is the result of more than a 50 year-long period of conservation and reconstruction work.
Trenčín became the centre of the re-catholicisation movement in the north western region of Old Hungary. In connection with this movement Jesuits built a large complex on the square in 1653-1657 comprising the single-nave Church and Monastery of St Francis Xavier. When the Jesuit order was abolished in 1776, the whole area passed to the Piarist order, who widened the area as far as Palacký street. The most recent modifications were made at the beginning of the 20th century.
The statue of the Holy Trinity, known as the plague column, stands in a park situated in the centre of Mierové námestie square. It was built in 1712 by Count Mikuláš Illésházy to commemorate the end of the plague epidemics. The town palace with its arcaded courtyard, originally belonging to the Illésházy family, is situated in the north east part of Mierové námestie square. It was rebuilt in 1764 and its three-storey building served as Župný dom (County House). Trenčín Museum is situated there today.
When the railway connection with Žilina was completed in the second half of the 19th century, Trenčín became an important commercial and industrial centre for the region of central Považie. At the start of the 20th century the four-storey Tatra Hotel decorated in Art Nouveau style was built under the castle rock. The Roman inscription on the castle rock dating from 179 CE may be seen from its rooms and from the summer terrace.
In 1913, the Jewish community built the synagogue in front of the Lower Gate at the Square of Ľudovít Štúr. This building in Romantic style contains features of Byzantine and Oriental architecture.
The historic core of Trenčín was declared a Town Conservation Reservation in 1987 with the aim of preserving the historical, artistic, town planning and architectonic values of this unique dominant feature of the central Považie region.