As we prepare for U.S. Secretary of State-designate Rex Tillerson to leave the private sector and enter public life for the first time, let’s take a look at how the Department of State defines the role of its leader.

Often called the “nation’s top diplomat,” the secretary of state had a hand in the shape of Washington since the first man to assume its office, Thomas Jefferson, brought his foreign affairs experience and encouraged U.S. expansion.

Jefferson was an aggressive secretary that complemented President Washington in his journey to establish the country as a world player, and the office has since remained mostly unchanged.

What exactly is the secretary of state’s role?

Along with advising the president on U.S. foreign relations, the secretary of state is responsible for negotiating international treaties and other agreements with countries either in conflict or that have a common cause.

He or she must also oversee the issuance of travel advisories, ensure protection of U.S. government property at home and abroad, and communicate world affairs back to citizens at home in America. Much of their time is spent traveling abroad, and the secretary of state is ultimately responsible for some 5,000 State Department employees stationed at 250 posts worldwide.

As the third-highest ranking official of the executive branch, the secretary of state ranks fourth in line for line to succeed the Presidency.

What kind of deals do they tend to make?

The Iran nuclear deal, or Joint Comprehensive Plan of Action — which President-elect Donald Trump has repeatedly vowed to tear to pieces — is one example of a treaty brokered through long discussions with other state actors that involve concessions and demands that create multilateral agreements.

Other examples of their duties abroad include the NAFTA trade agreement, advising on the secret mission to rescue American hostages in Iran, and securing the Strategic Defense Initiative to provide a weapons shield to Americans to protect her from ballistic missile attacks.

The current mission statement as provided by the State Department is to “Advance freedom for the benefit of the American people and the international community by helping to build and sustain a more democratic, secure, and prosperous world composed of well-governed states that respond to the needs of their people, reduce widespread poverty, and act responsibly within the international system.”

Do they often come from the private sector?

As he climbed toward his position as the Exxon Mobil CEO over 40 years at one of the nation’s most profitable publicly traded companies, Tillerson developed relationships with multiple world leaders — including Russia’s Vladimir Putin and Xi Jinping, China’s current president.

In the past, though, very few secretaries of state have come from the private sector. Only 9 of the previous 66 men and women who came before Tillerson actually accrued significant experience in business, making this an unconventional pick by Trump, who has promised to shake things up.

It does bring into question ethics concerns and conflicts of interest, especially in regards to a secretary’s equity and vesting options in their prior companies. Even within the GOP, a rocky confirmation hearing is expected to take place before the Trump Cabinet takes full shape.