Hebrew and Thaana scripts are other RTL writing systems that are official in Israel and the Maldives respectively.
The Arabic script is mostly but not exclusively right-to-left; mathematical expressions, numeric dates and numbers bearing units are embedded from left to right.
The Arabic-influenced Thaana alphabet which appeared around 1600 CE is used to write the Maldivian (Dhivehi) language.
Many other ancient and historic scripts derived from Aramaic inherited its right-to-left direction.
Ancient examples of text using alphabets such as Phoenician, Greek, or Old Italic may exist variously in left-to-right, right-to-left, or boustrophedon order; therefore, it is not always possible to classify some ancient writing systems as purely RTL or LTR.