De Keyser was an extremely prolific painter and is said to have produced more than 350 paintings. Having debuted with religious pictures, his attention was later drawn to his country's history. His breakthrough as a painter came with the canvas Battle of the Golden Spurs, which was exhibited at the Brussels Salon in 1836. It depicts a scene from an important historical battle between France and Flanders of 1302. Seeing the painting is said to have inspired the Belgian writer Hendrik Conscience to write his book "De Leeuw van Vlaanderen" (The Lion of Flanders) about the Flemish battle for independence from the French. The success of de Keyser's work was followed by his less impressive work, the "Battle of Worringen of 1288". Starting in 1862, de Keyser painted a series of decorative historical paintings that celebrated the Flemish school of art. The paintings were intended for the former Antwerp museum and academy building. When the new Royal Museum of Fine Arts in Antwerp was completed in the late nineteenth century, the paintings were transferred to the staircase of the museum.