This paper aims to identify the markedness constraints and constraint rankings responsible for limiting the Classical Arabic metra to a unique group of eight. To that end, the proposed account assumes the same basic principles and devices cross-linguistically utilised for the analysis of word-stress in natural languages. Mainly, constraints interpreting boundedness, headedness, quantity-sensitivity, exhaustivity, and extrametricality are formalised and ranked to assess constituency and metrical parsing. In particular, requirements on binarity applying on different levels of the metrical structure will demarcate the maximality and minimality boundaries for constituent moraicity and eventually define the domain for the metron. Other requirements on constituent headedness will distinguish the first seven of the eight metra as most harmonious. Like Sanskrit or Ancient Greek, Classical Arabic metre is basically considered to be quantitative, where weight mostly regulates the mapping to strong positions. Crucially, such mapping is established through a set of constraints unravelling the intrinsic prominence associated with the form of the uneven iamb, which features in the first seven metra, ruling out any implausible candidates that are possibly configured within that binarity domain. On another dimension, head verse foot non-finality, or more generally non-peripherality, coupled with final light syllable extrametricality create the environment for optimising the eighth metron, the final syllable of which is light.This paper aims to identify the markedness constraints and constraint rankings responsible for limiting the Classical Arabic metra to a unique group of eight. To that end, the proposed account assumes the same basic principles and devices cross-linguistically utilised for the analysis of word-stress in natural languages. Mainly, constraints interpreting boundedness, headedness, quantity-sensitivity, exhaustivity, and extrametricality are formalised and ranked to assess constituency and metrical parsing. In particular, requirements on binarity applying on different levels of the metrical structure will demarcate the maximality and minimality boundaries for constituent moraicity and eventually define the domain for the metron. Other requirements on constituent headedness will distinguish the first seven of the eight metra as most harmonious. Like Sanskrit or Ancient Greek, Classical Arabic metre is basically considered to be quantitative, where weight mostly regulates the mapping to strong positions. Crucially, such mapping is established through a set of constraints unravelling the intrinsic prominence associated with the form of the uneven iamb, which features in the first seven metra, ruling out any implausible candidates that are possibly configured within that binarity domain. On another dimension, head verse foot non-finality, or more generally non-peripherality, coupled with final light syllable extrametricality create the environment for optimising the eighth metron, the final syllable of which is light.