Oil paint as we know it today was developed during the Early Renaissance in Europe, around the 15th century. Jan van Eyck, a Flemish painter, is often credited with inventing it, but he actually only improved an earlier oil painting technique.
However, the use of oil as a medium in painting has a much older history. The earliest evidence of the use of oil in artwork dates back to the 7th century in western Afghanistan. The oil-based substances were used for Buddhist paintings, discovered in caves.
It’s important to note that throughout the centuries, different cultures have employed various forms of oil painting, using different types of oils and pigments. But the modern form of oil paint, as a primary medium for creating artworks, became popular from the 15th century onwards.