NOTE: Compare Ablative of Quality (§ 415) . In expressions of quality, the genitive or the ablative may often be used indifferently: as, praestantí prudentia vir, a man of surpasing wisdom; maximí animí homó, a man of the greatest courage. In classic prose, however, the genitive of quality is much less common than the ablative; it is practically confined to expressions of measure or number, to a phrase with eius, and to nouns modified by magnus, maximus, summus, or tantus. In general the Genitive is used rather of essential, the Ablative of special or incidental characteristics.
a. The genitive of quality is found in the adjective phrases eius modi, cuius modí (equivalent to tális, such; qualis, of what sort): -
b. The genitive of quality, with numerals, is used to define measures of length, depth, etc. (Genitive of Measure): -
For the Genitive of Quality used to express indefinite value, see § 417.