Rep. Rashida Tlaib, the first Palestinian-American member of Congress, will be sworn into office this week.

But unlike other incoming members of congress, she’ll take her oath on the Koran, Islam’s holiest book. And not just any Koran, either.

The Washington Post examined how the Koran, and this specific Koran — a 1734 English translation that belonged to Thomas Jefferson and sits in the Library of Congress — has a complicated history.

It’s an important sentiment for Tlaib, who told the Detroit Free Press that “a lot of Americans have this kind of feeling that Islam is somehow foreign to American history. Muslims were there at the beginning.” For similar reasons, Rep. Keith Ellison of Minnesota, America’s first Muslim member of congress, used Jefferson’s Koran when he took his oath into office in 2007.

Tlaib will also wear a traditional Palestinian robe, called a thobe.

But as the Washington Post notes, this translation was produced not out of appreciation for Islam, but to push Christian missionary efforts.

The introduction reads: “Whatever use an impartial version of the Korân may be of in other respects, it is absolutely necessary to undeceive those who, from the ignorant or unfair translations which have appeared, have entertained too favourable an opinion of the original, and also to enable us effectually to expose the imposture.”

While the translator George Sale wasn’t in favor of forced conversion, he did view Islam as foreign, and his introduction is often read as an example of the religious fear, misunderstanding and intolerance of the era.

Nevertheless, the Washington Post’s column argues that Jefferson’s Koran is appropriate for the occasion — “not in spite of the prejudice within it, but because of it.”

Alyssa Fisher is a news writer at the Forward. Email her at fisher@forward.com, or follow her on Twitter at @alyssalfisher