After the unification of the Iberian kingdoms, Portugal launched an expedition on the river in reverse from Francisco de Orellana, at the mouth of the river to the site of the present-day city of Quito, capital of Ecuador, with the intention of attaching Spanish lands (comprising the current territory of the Brazilian Amazon) to the Portuguese Kingdom. After the dissolution of the Iberian Union, Portuguese and Spanish possessions in the region were undefined, resulting in internal conflicts in the region between Portugal and Spain. The Portuguese Crown later asserted the principle of uti possidetis, with respect to the region. This was the first assertion of the principle from Roman law of "uti possidetis, ita possideatis", (Latin, "who has possession, has dominion"), analogous to English common law ""Squatters rights"". Due account may have been taken of John Locke's labour theory of property.