By the way the are speaking, their clothing and customs, the residents of Kostinbrod city belong to the shopi community.
It's hard to determine who were the first people living on those lands or when and where they came from. There are also many legends where the city's name comes from. According to one of them, in mid-13th century this was a small town and was named after the Constantine Asen Quiet when he rose to power in 1257. But another historical source states that the city was founded even earlier, because in one of the Ivan Asen II's deeds he expresses his wish for a monastery was build in Kostinbrod's village area.
Fortunately there is one credible source. The famous Mratchka deed given by king Ivan Alexander in 1347 to the Orehovski monastery "St. Nikola" located in the Mraka area near Izvor village (Radomir area). After mentioning village Belica located on both sides of Belitsa river (right tributary stream to Blato river), Kostinbrod is mentioned as the border to land given to the monastery. The deed is being kept in the Hilendarski monastery, and a there is a copy in Jordan Jovkov's work "Bulgarian antiques in Macedonia"
Turkish document from 1445 states that around that time Kostinbrod becomes part of Rakhabdar Mehmed's timar (temporary feodal domain) transfered to him from Balaban Kilari, having 37 households plus another 3 widows and 5 unmarried. There again are mentioned the names of the towns of Maslovo and Shiakovtsi, located near Kostinrod. It is known that Kostinbrod was even an administrative center for several towns in the area.
During the Bulgarian National Revival Kostinbrod's people are known as hardworking agrarians and breeders. Located on the very important road from Sofia to Lom and Vidin, the town prospers and expands. Bulgarian pride is awakened in the population. A big role undoubtedly play the nearby "St. Archangel Michael" monastery in Shiakovtsi village and the school opened years before the Liberation.
Kostinbrod's people represent themselves respectably in battles for enlightenment and justice. The Shiakov's monastery, where in 1872 Vasil Levski founds Revolution comittee, along with Sofia's comittee was one of the most important in the region.
The Favourable location and the agricultural and economical development after teh Libearation the number of households increases by a lot and around 1920 there are 237 families or 1185 people living in Kostinbrod. Build in 1912 the soup factory "Chilov" creates jobs for a lot of people. By 1940 the population increases to around 4000.
Looking for job a lot of people go down from the Balkan villages and settle in Kostinbrod and work in Sofia factories. Significant populatin increase is seen in September 1944. Chemical factories "Georgi Dimitrov", chicken farms and green crop factory are emerging. The science and research institues for farming, holticulture and other need hundreads of workers.
With a National comittee decree № 1942/12.04.1974, Kostinbrod is pronounced a city and villages Maslovo and Shiakovtsi are merged and named "Unity" and become a neighbourhood of Kostinbrod. In 30.12.1974 in a national newspaper says that Kostinbrod becomes administrative center for 14 other towns and villages, with Peturtch and Dragovishtitsa as some of the bigger ones