Thuluth (Persian:ثلث‎‎ sols, Turkish: Sülüs, from Arabic:ثلث‎ ṯuluṯ "one-third") is a script variety of Islamic calligraphy invented by Ibn Muqlah Shirazi. The straight angular forms of Kufic were replaced in the new script by curved and oblique lines. In Thuluth, one-third of each letter slopes, from which the name (meaning "a third" in Arabic) comes. It is a large and elegant, cursive script, used in medieval times on mosque decorations. Various calligraphic styles evolved from Thuluth through slight changes of form.