against humanity. Modern usage and form A treaty is an official, express written agreement that states use to legally bind themselves. It is also the objective outcome of a ceremonial occasion that acknowledges the parties and their defined relationships. There is no prerequisite of academic accreditation or cross-professional contextual knowledge required to publish a treaty. However, since the late 19th century, most treaties have followed a fairly consistent format. A treaty typically begins with a preamble describing the "High Contracting Parties" and their shared objectives in executing the treaty, as well as summarizing any underlying events (such as the aftermath of a war in the case of a peace treaty). Modern preambles are sometimes structured as a single very long sentence formatted into multiple paragraphs for readability, in which each of the paragraphs begins with a gerund (desiring, recognizing, having, etc.). The High Contracting Parties—referred to as either the official title of the head of state (but not including the personal name), e.g. His Majesty The King of X or His Excellency The President of Y, or alternatively in the form of " Government of Z"—are enumerated, along with the full names and titles of their Plenipotentiary representatives; a boilerplate clause describes how each party's representatives have communicated (or exchanged) their "full powers" (i.e., the official documents appointing them to act on behalf of their respective high contracting party) and found them in good or proper form. However, under the Vienna Convention on the Law of Treaties if the representative is the head of state, head of government or minister of foreign affairs, no special document is needed, as holding such high office is sufficient. The end of the preamble and the start of the actual agreement is often signaled by the words "have agreed as follows". After the preamble comes numbered articles, which contain the substance of the parties' actual agreement. Each article heading usually encompasses a paragraph. A long treaty may further group articles under chapter headings. Modern treaties, regardless of subject matter, usually contain articles governing where the final authentic copies of the treaty will be deposited and how any subsequent disputes as to their interpretation will be peacefully resolved. The end of a treaty, the eschatocol (or closing protocol), is often signaled by language such as "in witness whereof" or "in faith whereof", followed by the words "DONE at", then the site(s) of the treaty's execution