The Prado Museum in Madrid said on Thursday that “El Coloso,” right, the oil painting of a looming giant long attributed to Francisco de Goya, was probably painted by an assistant. The authenticity of the painting, which was created during Napoleon’s occupation of Spain, had been disputed by a Goya specialist at the museum, Manuela Mena, The Independent of London reported. “Stylistically, it is completely alien to Goya,” said Ms. Mena. “The person who painted the bulls in ‘El Coloso’ knew nothing about the anatomy of a bull, which Goya knew everything about.” José Luis Díez, a curator at the Prado, also claims that initials at the bottom corner of the work belong to Asensio Juliá, Goya’s assistant, The Telegraph reported. The painting has been omitted from “Goya in Times of War,” a special exhibition commemorating the bicentennial of the start of the Spanish War of Independence, which runs through July 13.