Though the merchants involved in Franco-Scottish trade operated within informal networks, they nonetheless adhered to a set of established traditions and codes of conduct. In addition to these informal rules, their activities were subject to a plethora of official regulations, all of which affected their ability to do business. During the early modern period commerce was regulated in a number of ways – financially through customs and excise rates, and more practically as activity was limited by prohibitions and restrictions on commodities or bans on travel to certain places. In wartime the role played by this legislation was more prominent, as it could be used as a tool by which the exchange of commodities and the movement of people to enemy nations was controlled, either by direct embargoes or through raising customs rates to such a level that they were prohibitive to trade. The very act of declaring war initiated such legislation; at the beginning of the Nine Years' War in 1689 the Scottish Privy Council stated, in declaring war on France, that they forbade ‘all the leidges of his Majesties antient kingdom of Scotland to trade, corospond or have any intercourse or medling with the said French King or any of his subjects’. It seems obvious that such legislation would have a negative impact on commerce – indeed the 1689 embargo, coupled with further restrictions on trade, has led to the view that Franco-Scottish commerce was virtually ruined thereafter.