to 29 of the 1899 Hague Convention for the Pacific Settlement of International Disputes. At the second Hague Peace Conference, the earlier Convention was revised by the 1907 Convention for the Pacific Settlement of International Disputes. The Conference was convened at the initiative of Czar Nicholas II of Russia "with the object of seeking the most objective means of ensuring to all peoples the benefits of a real and lasting peace, and above all, of limiting the progressive development of existing armaments." Functions PCA tribunals have jurisdiction for disputes based on the PCA founding documents (the Conventions on Pacific Settlement of International Disputes), or based on bilateral and multilateral treaties. Its Secretary General furthermore acts as an appointing authority for arbitration. Appointing authority When problems arise in designating arbitrators for an arbitration under UNCITRAL arbitration rules (e.g. because one of the parties refuses to designate an arbitrator, or when the designated arbitrators are unable to agree on designation of a third arbitrator), the PCA Secretary-General may be requested to serve as an appointing authority. This option is also open for other arbitration agreements, in which the Secretary General is designated. Between 2011 and 2015, 257 of such requests were submitted. Interstate arbitration based on the Hague Convention Arbitration between two states takes place when two member states of the PCA decide to submit a dispute for arbitration to a PCA Tribunal. The Tribunal consists of 5 arbitrators, two of which are selected by each party to the arbitration (and one of whom may be a national of the party concerned). The four arbitrators choose the fifth and presiding arbitrator. Interstate arbitration based on UNCLOS The United Nations Convention on the Law of the Sea (UNCLOS) provides for a dispute resolution mechanism regarding maritime boundaries in which member states can choose either the International Tribunal for the Law of the Sea International Court of Justice, arbitral tribunal (constituted in accordance with Annex VII, UNCLOS) a special arbitral tribunal (constituted in accordance with Annex VIII). If two member states have elected different dispute resolution measures, the third option is to be used. As of August 2016, the PCA has administered 12 cases initiated by States under Annex VII to the UNCLOS, thus administering all cases initiated under this Annex except for one. Investorstate investment disputes Many free trade agreements provide for a mechanism to resolve disputes between investors and states through arbitration