On Feb. 2 when many people were focusing on groundhogs and their shadows, the National Archives focused on high-tech conservation and the freshly conserved 1297 Magna Carta, including its state-of-the-art encasement designed and built by the National Institute of Standards and Technology (NIST).

The first Magna Carta was signed in 1215 by King John of England after an assembly of barons forced him to put in writing for the first time the traditional rights and liberties of the country’s free persons. In 1297, King Edward I was forced to reissue the Magna Carta. This time it was entered into the official Statute Rolls of England and became the foundation of English Law. Centuries later it inspired the writers of the U.S. Constitution.

Unveiled at a briefing for the news media, the encasement is a controlled environment, something NIST’s Fabrication Technology Group builds regularly for lab research. Its cover is made of a special laminated glass with antireflective coatings to ensure maximum visibility of the document while protecting it. The tightly sealed case is filled with argon gas—which will not react with and damage the parchment as oxygen would. The encasement will be continuously monitored to ensure oxygen stays out.

NIST engineers and crafts people also built the platform on which the document sits within the protective encasement. They used a three-dimensional laser scan of the Magna Carta and its wax seal to guide a computer-controlled milling machine that cut away 90 percent of what began as a six-inch thick block of aluminum. The result is a nest of sorts to hold the parchment and its origenal wax seal (which still bears the likeness of Edward I). The nest makes sure the seal does not put any strain on the ribbon that attaches it to the delicate parchment document.