Thuluth (Persian: ثلث sols, Turkish: Sülüs, from Arabic: ثلث ṯuluṯ “one-third”) is a script variety of Islamic calligraphy invented by the Persian Ibn Muqlah Shirazi, which made its first appearance in the 11th century CE (fourth Hijri). 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.
“Thuluth” means “one-third.” This possibly refers to its pen size (one-third the size of the pen used for a larger script called tumar)
Script par excellence for writing many different kinds of texts
Used particulary for titles and architectural inscriptions
Thuluth is most often written in conjunction with naskh. Naskh, however, is not based on the Thuluth script, it is merely a smaller companion script
Developed in the 10th century
Refined by Seyh Hamdullah in the 15th century
Still in use today
Vertical strokes have a leftward slant, horizontals have a deep curve
The ends of most descending letters come up in a hook
Often written so the letters interlace
Many alternate letter forms exist in this script
Thuluth is often considered the most powerful and versatile script. Some experts say you are not a calligrapher until you can write thuluth.