The legislation that Republican Gov. Jeff Landry signed into law on Wednesday requires a poster-sized display of the Ten Commandments in “large, easily readable font” in all public classrooms, from kindergarten to state-funded universities.

“If you want to respect the rule of law, you’ve got to start from the original lawgiver, which was Moses” who got the commandments from God, Landry said.

Opponents questioned the law’s constitutionality and vowed to challenge it in court. Proponents said the measure is not solely religious, but that it has historical significance. In the language of the law, the Ten Commandments are “foundational documents of our state and national government.”

The posters, which will be paired with a four-paragraph “context statement” describing how the Ten Commandments “were a prominent part of American public education for almost three centuries,” must be in place in classrooms by the start of 2025.

Under the law, state funds will not be used to implement the mandate. The posters would be paid for through donations.

The law also “authorizes” but does not require the display of other items in K-12 public schools, including: The Mayflower Compact, which was signed by religious pilgrims aboard the Mayflower in 1620 and is often referred to as America’s “First Constitution”; the Declaration of Independence; and the Northwest Ordinance, which established a government in the Northwest Territory — in the present day Midwest — and created a pathway for admitting new states to the Union.

Not long after the governor signed the bill into law at Our Lady of Fatima Catholic School in Lafayette on Wednesday, civil rights groups and organizations that want to keep religion out of government promised to file a lawsuit challenging it.

The law prevents students from getting an equal education and will keep children who have different beliefs from feeling safe at school, the American Civil Liberties Union, Americans United for Separation of Church and State, and the Freedom from Religion Foundation said in a joint statement Wednesday afternoon.

“Even among those who may believe in some version of the Ten Commandments, the particular text that they adhere to can differ by religious denomination or tradition. The government should not be taking sides in this theological debate,” the groups said.

The controversial law, in a state ensconced in the Bible Belt, comes during a new era of conservative leadership in Louisiana under Landry, who replaced two-term Democratic Gov. John Bel Edwards in January. The GOP holds a supermajority in the Legislature, and Republicans hold every statewide elected position, paving the way for lawmakers to push through a conservative agenda.

Similar bills requiring the Ten Commandments be displayed in classrooms have been proposed in other states including Texas, Oklahoma and Utah. However, with threats of legal battles over the constitutionality of such measures, no state besides Louisiana has succeeded in making the bills law.

Legal battles over the display of the Ten Commandments in classrooms are not new.

In 1980, the U.S. Supreme Court ruled that a similar Kentucky law was unconstitutional and violated the establishment clause of the U.S. Constitution, which says Congress can “make no law respecting an establishment of religion.” The high court found that the law had no secular purpose but rather served a plainly religious purpose.

Associated Press reporter Jeffrey Collins in Columbia, South Carolina, contributed to this report.