As documented by numerous archeological findings in town’s territory, beginnings of settlement go back up to prehistoric times. It was densely populated already 30.000 years ago. Villages of first agrarian inhabitants had been in the area of town already 6.000 years ago.
The territory of today’s Nitra was an important centre of the Celts (already few centuries BC), then of Germanic people and finally of the Slavs. It was residence of first known rulers in the territory of today’s Slovakia - germanic tribes of Quadi (around 396 AD, disputable) and from the 8th century to 1108 it was a residence of the Principality of Nitra.
Findings from richely equipped burial sites come already from the 9th century. Archeological research have documented existence of several Romanesque ecclesiastic buildings.
In the first third of the 9th century it was a residence of the prince Pribina, the town was then one of the centres of the Great Moravia. Agglomeration of Nitra used to be bigger than present-day town at the time of Great Moravia and in the post-Great Moravian period. The first known Christian church of the Central and Eastern Europe, built in 828, is situated in Nitra. Nitra was a residence of the first diocese (episcopal office) in the territory of Slovakia (from 880). The town had its boom in the Early Middle Ages during government of ruler Svätopluk, the prince of Nitra from about 850 to 871 and then the ruler of Great Moravia until 894. During his government the first known monastery in Slovakia was built at Zobor in 880-881. Under his rule Nitra consisted of five fortified villages and 20 marketplaces what gives evidence of its importance. There were already several churches in Nitra and surroundings between the 9th and the 10th century: Nitra Castle, Párovce, Nitrianska Blatnica, Lupka, Zobor and Kostoľany pod Tribečom. Outside the town’s borders there were other Great Moravian settlements - Chrenová, Lupka, Branč, Vráble and Zlaté Moravce. Saints Cyril and Methodius, authors of Glagolitic alphabet (precursor of the Cyrillic) were actively participating on development of the Church and of the first known diocese in the territory of Slovakia. Basilica discovered under the Nitra Castle may be that first Christian church of western and eastern Slavs from 828.
From the end of the 10th century (excluding 1001-1030) the town was property of Arpads, around 1083 or 1100 the Diocese of Nitra was renewed. In 1248 Nitra became a royal town, but forty years later the king gave it along with castle to bishops of Nitra. Nitra’s transformation from royal town into territorial lord’s town had far-reaching consequences. Town got into lower legal category, but as episcopal residence and important castle it was still an important centre.
In 1633-1634 it was occupied by Turks during their invasions.
From the half of the 18th century Nitra was spared from military hardships, what enabled reconstruction of town and castle, mainly of the cathedral.
As a consequence of development of construction the number of inhabitants in the 19th century exceeded 10.000 and administration became more complicated. In 1873 Nitra became a town with the established municipal authority with mayor at the head and with numerous municipal governments. Further town’s development was strongly influenced by the two World Wars. In the new Czechoslovak Republic Nitra became headquarters of the county. The World War II was followed by period of tempestuous expansion of construction, but many architectonic monuments were damaged. Nevertheless, Nitra acquired many schools, both scientific and cultural public bodies and it had become a centre of Slovak agricultural education system, science and production.
The most famous monument is the castle from the 11th century, rebuilt in the 15th century and then again in the period of Baroque.