Analysis of information sources in references of the Wikipedia article "Long s" in English language version.
sǒ·lidus, n. (pl. -di). (Hist.) gold coin introduced by Roman Emperor Constantine; (only in abbr. s.) shilling(s), as 7s. 6d., £1 1s.; the shilling line (for ſ or long s) as in 7/6. [LL use of L SOLIDus](The name shilling is derived from a Roman coin, the solidus.)