collatio lustralis (Gk. Χρυσάργυρον)
Tax, instituted by Constantine I and collected every four years (lustrum) from merchants and traders. Anastasius I abolished it in the East in 498; Joshua the Stylite (31) describes the week’s festival at Edessa celebrating its abolition. It was payable in both gold and silver, but nearly all laws after 372 mention payment only in gold (CTh XIII, 1). This tax was levied upon individual tradesmen, including all craftsmen, market gardeners, fishermen, merchants, and prostitutes, irrespective of income or the level of trade engaged in; it was in no way a sales tax. Those in the imperial administration, those selling the produce of their own land, and certain clerics were exempt. Representatives from each particular trade were responsible for tax collection and the management of exemptions on a local level. It is not clear what proportion of state revenue this tax raised, although according to several ancient authors, the tax was an enormous burden on those subject to it (Libanius, Oration, 46, 22; Zosimus, II, 38; Evagrius, HE III, 39). The proceeds paid for provisions for the troops and other public expenditure.