In the early 18th century, Leibniz outlined his characteristica universalis, an artificial language in which grammatical and logical structure would coincide, which would allow reasoning to be reduced to calculation. Leibniz acknowledged the work of Ramon Llull, particularly the Ars generalis ultima (1305), as one of the inspirations for this idea. The basic elements of his characteristica would be pictographic characters representing unambiguously a limited number of elementary concepts.