Ihtisab, or ihtisap was a type of tax on markets in the Ottoman Empire; the muhtasib or ihtisap ağasi - the ihtisab collector - had a broader role in regulating and taxing markets under the authority of the kadı. In the later empire, damga resmi (a charge on hallmarks, and stamp duty) was considered to be part of ihtisab. In the early 19th century, before the tanzimat reforms, the difficulty of enforcing ihtisab led the Ottoman government to establish a series of monopolies, called ved-i vahit, to ease collection