The Appearance of the Horizon Line in Persian Painting Based on the Illustrations on both Ceramics and manuscripts from Seljuk to Ilkhanid Period

The horizon line is the most important element in landscape paintings and demarcates the sky and the ground. The horizon line organizes all the visual items in, both the sky and the ground sections in the picture, logically. Although drawing the horizon line is a common method in painting nowadays, analyzing pre-Timurid illustrated Persian or Arabic manuscripts revels that the artists did not know about the efficiency of the line at the beginning in 11^th century. Therefore, in these paintings, both on the ceramics and in the Persian or Arabic illustrated manuscripts, the visual elements are observed suspended and weightless. Up until late 14^th century when Ilkhanid School emerged in Tabriz, Persian painters used to test various drawing styles to find and regulate a specific method that enabled them to arrange the visual elements in the areas of sky and ground and eliminate the suspension and weightlessness in the space of their paintings. They invented several methods that particularly have survived in the illustrated Arabic and Persian manuscripts. These illustrated manuscripts enable us to discuss the innovative methods of Persian painters. Including the sky line, the basin level, the frame-level and the ground line are the most frequent methods used in these manuscripts. Finally, in the 14^th-century-Tabrizid manuscripts, the horizon line appeared. Achieving this appearance, the Persian picture space both in the ground and sky expanded logically; as a result, the visual elements in these spaces started to seem more grounded and as if possessing weight; diverse visual levels were arranged on the ground and the vertical perspective emerged.
 This article focuses on the details of those primitive methods mentioned above, which led to the appearance of the horizon line and the results of this. The article analyzes more than 30 illustrated ceramics and 300 paintings in 40 remarkable manuscripts from the 11^th to the 14^th centuries and concludes that: In the sky-line method, a blue curved part was used in the highest section of the painting as the sky. In some paintings, a line near the picture frame in the lowest section of the painting made the second part represent the ground. Between two parts, the largest segment of the painting used to get located where in all the visual elements look undecided and pending. In the basin-level method, the most important part of the painting is a basin that is represented by a blue surface decorated by plants and rubbles. Other visual elements are arranged around the basin. In the frame-level method, the lowest part of the frame picture, as the ground level, carries the visual elements. In this method, the biggest part of the painting forms an unaffected background. Because of this background, the represented space does not have any perspective. The ground-line is the most practical method. In this, the narrow surface, almost colored dark green, a little above the bottom line of the frame picture plays the role of the ground and caries all the visual elements.