- Prince Michael the Brave set up Ploiesti in 1601, turning it into a boomtown
- The 18th century and early 19th century were marked by the development of
trade, exploitation and processing of natural resources – including oil, which always had
a special role, that keeps this day;
- In the 17th century began the salt exploitation in Slanic Prahova salt deposit.
Currently, the resort houses a spa and the largest salt mine in Europe;
- In 1857, Romania was the first country with an officially certified oil production – 275 tons, which was reported in “The Science of Petroleum Encyclopaedia English Book”
- In 1875 began operating the “Mehedinteanu” refinery in Ploiesti, the first in the world;
- In 1904 was founded in Campina the first school for driller foremen in the world;
- In 1908 were established in Ploiesti the “Concordia” workshops for the repair and manufacture of oil machinery, which were the precursor to the famous oil equipment
manufacturing companies of today;
- Between 1950 – 1957 were established in Prahova county research and design institutes for oil and gas surveying, drilling, extraction, transportation and processing
as well as for oil equipment;
- Since 1967, the Oil and Gas University runs in Ploiesti, having oil specialized oil faculties – Oil and Gas Engineering, Petroleum and Petrochemical Technology –
unique in Eastern Europe.
- In Prahova county operate four refineries: Petrobrazi (OMV Petrom), Vega (Rompetrol) Petrotel-Lukoil (Lukoil) and Steaua Romana.