The Templar Constitution was an article written in 118 BBY by the Twilight Council that established all Templars laws regarding the Templars themselves and the territory they controlled and took care of. It was added to periodically through the years with various amendments and addendums. One of the last changes was made in 137 ABY after the crisis during the Sith Imperial War. Another change wasn't made after that until 376 ABY when the Templars took control of the planet Acroxx.