The prominence of commercial issues in 17th and 18th century diplomacy derived from the economic theory of Mercantilism, which viewed global trade as finite.
Increasing your share meant taking it from others, so states protected their own using tariffs or import bans, while attacking the colonies or ships of others.
English complaints related to two areas; exclusion from markets within the Spanish Empire, and restrictions on direct trade between mainland Spain and England.

The 1630 treaty was annulled and on 23 May 1667, England and Spain signed two new treaties; a commercial deal and an agreement by England to mediate a truce between Portugal and Spain.
In a separate article, each party undertook not to assist enemies of the other; England would withdraw its Portuguese expeditionary force, while Spain remained neutral in the Anglo-Dutch war.

The commercial treaty consisted of forty separate articles, the most important being Article Seven, part of Fanshawe's draft but omitted from the original terms.
English merchants were given equal status with the Dutch and granted the right to import goods tax free into European Spain.
Articles Seven, Eight, Eleven and Twelve went further than this, by allowing English colonies in North America and the East India Company to ship goods direct to Spanish ports.

By granting English merchants trading rights within Spanish America, the treaty accepted England's presence in the Caribbean and occupation of Jamaica, although this was not formally recognised until 1670.
Article Ten broadly exempted English ships and warehouses in Spanish ports from customs inspections, disputes being referred to a local judge, nominated by the English and confirmed by Madrid.

Articles Fourteen through Seventeen allowed English ships access to ports throughout the Spanish Empire, a significant concession since it greatly increased their operating range.
Article Thirty-Eight made English merchants equivalent to the Dutch and French by awarding them most favoured nation status; its implementation was resisted by Spanish merchants and had to be re-iterated in the 1670 Treaty.

These concessions were the first step in challenging Dutch economic supremacy outside Europe and thus of greater significance than often appreciated; they remained in place until the outbreak of the War of the Spanish Succession in 1701.
The prominence of commercial issues in 17th and 18th century diplomacy derived from the economic theory of Mercantilism, which viewed global trade as finite. Increasing your share meant taking it from others, so states protected their own using tariffs or import bans, while attacking the colonies or ships of others. English complaints related to two areas; exclusion from markets within the Spanish Empire, and restrictions on direct trade between mainland Spain and England.
The 1630 treaty was annulled and on 23 May 1667, England and Spain signed two new treaties; a commercial deal and an agreement by England to mediate a truce between Portugal and Spain. In a separate article, each party undertook not to assist enemies of the other; England would withdraw its Portuguese expeditionary force, while Spain remained neutral in the Anglo-Dutch war.
The commercial treaty consisted of forty separate articles, the most important being Article Seven, part of Fanshawe's draft but omitted from the original terms. English merchants were given equal status with the Dutch and granted the right to import goods tax free into European Spain. Articles Seven, Eight, Eleven and Twelve went further than this, by allowing English colonies in North America and the East India Company to ship goods direct to Spanish ports.
By granting English merchants trading rights within Spanish America, the treaty accepted England's presence in the Caribbean and occupation of Jamaica, although this was not formally recognised until 1670. Article Ten broadly exempted English ships and warehouses in Spanish ports from customs inspections, disputes being referred to a local judge, nominated by the English and confirmed by Madrid.
Articles Fourteen through Seventeen allowed English ships access to ports throughout the Spanish Empire, a significant concession since it greatly increased their operating range. Article Thirty-Eight made English merchants equivalent to the Dutch and French by awarding them most favoured nation status; its implementation was resisted by Spanish merchants and had to be re-iterated in the 1670 Treaty. 
These concessions were the first step in challenging Dutch economic supremacy outside Europe and thus of greater significance than often appreciated; they remained in place until the outbreak of the War of the Spanish Succession in 1701.
Treaty of Madrid (1667)