Chernihiv is a historic city in northern Ukraine, which serves as the administrative center of the Chernihiv Oblast (province), as well as of the surrounding Chernihiv Raion (district) within the oblast. Administratively, it is incorporated as a city of oblast significance. Population: 294,727 (2015 est.)
Chernihiv was first mentioned in the Rus'-Byzantine Treaty (907) (as Черниговъ (Chernigov)), but the time of establishment is not known. According to the items uncovered by archaeological excavations of a settlement which included artifacts from the Khazar Khaganate, it seems to have existed at least in the 9th century. Towards the end of the 10th century, the city probably had its own rulers. It was there that the Black Grave, one of the largest and earliest royal mounds in Eastern Europe, was excavated in the 19th century.
In the southern portion of the Kievan Rus' the city was the second by importance and wealth. From the early 11th century it was the seat of powerful Grand Principality of Chernigov, whose rulers at times vied for power with Kievan Grand Princes, and often overthrew them and took the primary seat in Kiev for themselves. The grand principality was the largest in Kievan Rus and included not only the Severian towns but even such remote regions as Murom, Ryazan and Tmutarakan. The golden age of Chernihiv, when the city population peaked at 25,000, lasted until 1239 when the city was sacked by the hordes of Batu Khan, which started a long period of relative obscurity.
The area fell under the Grand Duchy of Lithuania in 1353. The city was burned again by Crimean khan Meñli I Giray in 1482 and 1497 and in the 15th to 17th centuries it changed hands several times between Lithuania, Muscovy (1408–1420 and from 1503), and the Polish-Lithuanian Commonwealth (1618–1648), where it was granted Magdeburg rights in 1623 and in 1635 became a seat of Chernihiv Voivodeship. The area's importance increased again in the middle of the 17th century during and after the Khmelnytsky Uprising. In the Hetman State Chernihiv was the city of deployment of Chernihiv Cossack regiment (both a military and territorial unit of the time).
Chernihiv has a humid continental climate(Köppen Dfb) with cold, cloudy and snowy winters, and warm, sunny summers. The average annual temperature for Chernihiv is 7.0 °C (44.6 °F), ranging from a low of −5.6 °C (21.9 °F) in January to a high of 19.5 °C (67.1 °F) in July. Precipitation is well distributed throughout the year though precipitation is higher during the summer months and lower during the winter months. The record high was 39.0 °C (102.2 °F) and the record low was −36.0 °C (−32.8 °F).
Chernihiv's architectural monuments chronicle two most flourishing periods in the city's history - those of Kievan Rus' (11th and 12th centuries) and of the Cossack Hetmanate (late 17th and early 18th centuries.)
The oldest church in the city and one of the oldest churches in Ukraine is the 5-domed Transfiguration Cathedral, commissioned in the early 1030s by Mstislav the Bold and completed several decades later by his brother, Yaroslav the Wise. The Cathedral of Sts Boris and Gleb, dating from the mid-12th century, was much rebuilt in succeeding periods, before being restored to its original shape in the 20th century. Likewise built in brick, it has a single dome and six pillars. The crowning achievement of Chernihiv masters was the exquisite Pyatnytska Church, constructed at the turn of the 12th and 13th centuries. This graceful building was seriously damaged in the Second World War.
Its original medieval outlook was reconstructed to a design by Peter Baranovsky. The earliest residential buildings in the downtown date from the late 17th century, a period when a Cossack regiment was deployed there. Two most representative residences are those of Polkovnyk Lyzohub (1690s) and Polkovnyk Polubutok (18th century). The former mansion, popularly known as the Mazepa House, used to contain the regiment's chancellery. One of the most profusely decorated Cossack structures is undoubtedly the ecclesiastical collegium, surmounted by a bell-tower (1702). The archbishop's residence was constructed nearby in the 1780s. St Catherine Church (1715), with its 5 gilded pear domes, traditional for Ukrainian architecture, is thought to have been intended as a memorial to the regiment's exploits during the storm of Azov in 1696.