The treaty stipulated that no tax higher than the tax charged for an equal amount of French wines could be charged for Portuguese wines (but see below) exported to England, and that English textiles would be admitted to Portugal at all times, regardless of the geopolitical situation in each of the two nations (to ensure England would still accept Portuguese wine in periods when not at war with France).[1][2]
The Methuen Treaty has been the subject of diverse interpretations.[3] Detractors, including Luís da Cunha, argued that the influx of English woollens led to the decline of the Portuguese wool industry.[4][5] Additionally, emphasis on wine production, while bringing prosperity to certain regions, left Portugal heavily reliant on England as its primary wine buyer.[6] Critics contended that the focus on wine came at the expense of other agricultural sectors[7] and redirected the nation away from its path towards industrialization.[8][9][10]
In defense of the treaty, it's been asserted that Portugal lacked the necessary resources for substantial manufacturing endeavors,[11][3] and its industries were already grappling with stagnation.[7] Furthermore, some believed that the treaty did not confine Portugal's trade;[3] instead, it played a pivotal role in augmenting the overall prosperity of the nation through increased commerce[1] and stronger ties with England.[11][12][13]