Trade is the third of the Economic <l:6,66>Advances<e>. Thanks to the <l:4,7>Domestication<e> pack animals allow farmers, merchants and miners to carry wares to distant but profitable locales and the Trade is born. Development of local economy centres is organised around the <l:2,10>Marketplace<e>, which greatly increases economic power of the city. The rise of Trade also allows a Civilization to employ <l:1,54>Mistress<e>, the first spying unit.