The area of the wooded area on the Prahova Valley where Sinaia is today was uninhabited in the 17th century, the first inhabitants settling in the virgin forest here at the foot of the Bucegi Mountains, being the monks of the Sinaia monastery, founded between 1690 - 1695 by the great backpacker Mihai Cantacuzino, as well as some scouts who were in charge of guarding the monastery and cultivating its mosques. The city took the name of the monastery, and the monastery was named after the back trip to Saint Catherine's Monastery in the Sinai Peninsula.
At the beginning of the 19th century, the entire Prahova Valley was organized as a single commune, called the Black Bridge, covering the entire valley, from Predeal to Posada. In 1864 Posada and Negru Bridge were annexed to the commune of Comarnic.
On August 5, 1866 Prince Carol I of Romania reached the Sinaia Monastery, situated at that time in the Podul Neagului commune. He was involved in the organization of the region and, in 1874, the cattle that remained outside Comarnic were named Sinaia, a commune residing at Busteni. A report dated December 1, 1874, confirms that the residence of the Podul Neagului was moved to Sinaia, which received its name in that year (from that of the Sinaia Monastery, whose name comes from the Mountain Sinai).
In the city of Sinaia there are eleven historical monuments of national interest architecture: Sinaia Casino (1912-1913); Hotel Caraiman (1911); Alina Stirbei Villa (1875, now Financial District of Sinaia); villa Emil Costinescu (1892, with extensions between 1918-1939); the ensemble of the Sinaia railway station, consisting of the royal station (1870) and the train station (1930-1940); the house of historian Nicolae Iorga (1918); Hotel "Furnica" (end of the 19th century); Hotel "Palace" (1911-1912); Villa Take Ionescu (early twentieth century); the house of composer George Enescu (1923-1926); Sinaia monastery (1690-1695), ensemble made up of the "Assumption of the Virgin Mary" church, chapel, abbey, cells and wall of the old enclosure; Last but not least, the Peles castle complex (1873-1883), made up of the castle itself, the Pelisor castle, the Foisor castle, the Economat villa, the electric mill (the former mill of the Sinaia monastery), the Ceramic House, the Knights' Villa, Casa Veche, Casa Noua Villa, villas A, B and C, and the park. Also of national interest are the public monument represented by the bust of the actor Ion Iancu Brezieanu (1935) located in the central park "Dimitrie Ghica", as well as the memorial or funeral monuments of the hero cemetery of the First World War (beginning of the 20th century) and The Cave of Take Ionescu (1922) located in the old premises of the Sinaia Monastery.