At this stage of the negotiations matters were further complicated (1) by the negotiation of the Cass-Yrissari treaty of November 16, 1857, between the United States and Nicaragua for protection of the transit route and (2) by the invasion of Nicaraguan territory by a band of filibusters under General Walker, bent on the subversion of the lawful government of the country. The treaty was not ratified, however, and the Walker expedition was arrested by the interposition of the United States navy. The United States government not having given any definite answer to the British proposal to submit the treaty to arbitration, the British government delayed dispatching Sir William Ouseley on his mission. In the negotiations which took place during this delay the question of the abrogation of the Clayton-Bulwer treaty was discussed between the two governments. In his message of December 8, 1857, President Buchanan had suggested the abrogation of the treaty by mutual consent as the wisest course that could be pursued in view of the increasing complications to which the varying constructions of it were giving rise. The British government took up this suggestion and expressed its willingness to concur in such a course, but also expressed the opinion that the initiative should be taken by the government which was dissatisfied with its provisions. The British minister was, however, directed by his government to make it perfectly clear to the government of the United States, that to abrogate the treaty was to return to the _status quo ante_ its conclusion in 1850; that Great Britain had no kind of jealousy respecting American colonization in Central America, and did not ask or wish for any exclusive privileges whatever in that quarter.[161] Finally, Sir William Ouseley was dispatched on his mission and during the years 1859 and 1860 succeeded in negotiating treaties with Guatemala, Honduras, and Nicaragua, the provisions of which were in substantial accord with the rejected Dallas-Clarendon treaty.[162] The treaty with Nicaragua signed at Managua, January 28, 1860, though restoring to that republic nominal sovereignty over the Mosquito territory, reserved to the Indians the right of retaining their own customs, assigned boundaries to that reservation in all probability greatly beyond its true limits, and confirmed grants of land previously made in that territory. Notwithstanding these facts, in his annual message of December 3, 1860, President Buchanan declared that the United States government was satisfied with the final settlement. His words were: The discordant constructions of the Clayton-Bulwer treaty between the two governments, which at different periods of the discussion bore a threatening aspect, have resulted in a final settlement entirely satisfactory to this government.[163]