Abjad numerals as an absolute dating method: Forts from Al-Ain, UAE

The Abjad numerals are a decimal system, where the numerical value of the 28 Abjad letters are used to denote construction dates in a word, phrase or a hemistich inscribed on the façades of old Islamic buildings. The system is precise and accurate but has only been researched sporadically. Therefore, this study is concerned with describing, analyzing, and documenting the historical dimension and the major uses of the Abjad numeral system in the Arab region. It illuminates its use as a poetic chronogram to determine the construction dates of two case studies in Al-Ain (UAE); al-Jahili Fort and the Eastern Fort, which have been dated to the late 19^th and early 20^th centuries, respectively. The engraved verses (poems) are deciphered and discussed in comparison to other parallel examples from Jordan, Saudi Arabia, and Egypt, in order to determine the major characteristic features of poetic chronograms. Additionally, the study traces the roots of the idea of assigning numerical values to the writing signs in Mesopotamia and its surrounding region since the late third millennium BCE. It concludes that using Abjad numerals embedded in a word in a chronogram is similar to the Greek inscriptions found from different archaeological sites in the 3^rd and 4^th centuries CE, while the earliest recorded poetic chronogram relates to a later date around the 14^th century. Finally, the study recommends that further documentation of chronograms should be undertaken, due to their historical value as well as the necessity to provide an accurate, absolute date for individual structures.