The task of the Chamber was to resolve the land, island and maritime dispute between El Salvador and Honduras by the law. Article 5 of the Special Agreement of 24 May 1984 defines applicable law in broad and general terms: In accordance with the provisions of the first paragraph of Article 38 of the Statute of the International Court of Justice, the Chamber, when delivering its Judgment, will take into account the rules of international law applicable between the Parties, including, where pertinent, the provisions of the General Treaty of Peace. The parties did not expressly referred to the principle uti possidetis juris. It is without doubt that they agreed that it was the main principle applicable to the dispute. Still, if the parties were limited the applicable law just to this principle, the Chamber would have much more complicated job. The broad and general determination of the applicable law facilitated a judicial resolution of the dispute. It allowed the Chamber to apply other rules that completed or substituted the application of uti possidetis juris. The Chamber had at its disposal a lot of title-deeds to commons, it is acts of colonial Spanish authorities granting lands to Indian communities that lived in villages in various provinces which became parts of El Salvador or Honduras. A border of lands granted to Indian villages, one of which was located in Salvadorian province and the other in Honduran province, has been transformed by the effect of the principle uti possidetis juris or precisely by colonial effectivités into an inter-state frontier. It was the first method, used by the Chamber, to determine the frontier. However, the Chamber considered that uti possidetis frontier is subjected to changes by mutual consent of the parties over the times. It did not hesitate to take into account mutual consent even acquiescence as a method of determination of the frontier. The Chamber had at its disposal records of previous numerous negotiations of the two parties, related to determination of the frontier. The records were disclosing consent of the parties on some sections of the disputed frontier that has not reached the form of an international treaty binding to the parties. The Chamber used to confirm such consent of the parties as their acceptance of mutual frontier and, in such occasions, it did not investigate title deeds related to these sectors. The Chamber investigated evidences, submitted by the parties, on exercise of their powers in dispute areas. It was done to explore whether effective exercise of power of one or other party required a correction of uti possidetis frontier. There was no case where the Chamber found that principle of effectivités asked the correction uti possideties frontier. The Chamber took into account, also, topography and by an occasion it changed a little bit uti possidetis frontier to provide topographically superior boundary line. Also, it applied the customary rule that the frontier follows the middle of the bed of a non-navigable river. In such a way, the Chamber resolved the dispute by application of uti possidetsi juris principle as the basic principle which was supplemented or substituted by other rules of international law.