Modernism was an aesthetic trend that emerged in the early twentieth century in opposition to the adornment of preceding forms. Modernism made advantage of new materials and technology to create simple, attractive forms that could be mass-produced. The term "modern art" is often used as a synonym for "20th-century art", but this is incorrect: modern artists such as Pablo Picasso and Henri de Toulouse-Lautrec were not necessarily involved in producing work that was considered modern at the time. Modern architecture developed during the same period and shares many principles with modern art and design. Architects such as Le Corbusier and Ludwig Mies van der Rohe promoted the use of straight lines, clear shapes, functional materials, and simplicity in order to achieve maximum efficiency and economy of construction. Although they were trained as architects, many modern artists were also designers who used their own creative talents to come up with innovative solutions to architectural problems. In fact, some consider Piet Mondrian to be the first true modern artist because he developed a systematic way of thinking about painting that was later adopted by many other artists. Modern design originated in the late nineteenth century when prominent artists began to incorporate industrial design elements into their works. By the 1920s, modern design had become a widely accepted term for describing simple, elegant objects that were in contrast to the ornamental styles then popular among decorative artists.