Pi Tau Sigma is an International Mechanical Engineering Honor Society. Pi Tau Sigma's core values are:

Pi Tau Sigma came into being on March 16, 1915, at the University of Illinois. A similar organization embarked November 15, 1915, at Wisconsin. The two schools met together early in 1916 to make the honor society national, under the name of Pi Tau Sigma. The coalition took place in Chicago, March 12, 1916. To date, 167 chapters have been inducted into the organization throughout the United States with 157 still active. Pi Tau Sigma honors Mechanical engineering students who have exemplified the "principles of scholarship, character and service..." in the Mechanical engineering profession

Both undergraduate and graduate students are eligible to join Pi Tau Sigma based on academic achievement. Juniors in the top 25% of their class and seniors in the top 35% of their class, based on grades, are invited to join. Membership fees are due at initiation and membership lasts a lifetime.

Pi Tau Sigma members are chosen on a basis of sound engineering ability, scholarship, personality, and probable future success in their chosen field of Mechanical Engineering. There are three grades of membership: Honorary, Graduate, and Active. Honorary members are technical graduates actively engaged in engineering work, or members of mechanical engineering faculties. graduate membership is conferred upon persons who would have been eligible had Pi Tau Sigma been established earlier in schools not having chapters, or upon those continuing graduate study. Active members are selected from the junior and senior mechanical engineering classes at their respective schools whose mechanical engineering curriculum must be accredited by the A.B.E.T.

King Arthur is a legendary British leader of the late 5th and early 6th centuries, who, according to medieval histories and romances, led the defence of Britain against Saxon invaders in the early 6th century. The details of Arthur's story are mainly composed of folklore and literary invention, and his historical existence is debated and disputed by modern historians. The sparse historical background of Arthur is gleaned from various sources, including the Annales Cambriae, the Historia Brittonum, and the writings of Gildas. Arthur's name also occurs in early poetic sources such as Y Gododdin.

The legendary Arthur developed as a figure of international interest largely through the popularity of Geoffrey of Monmouth's fanciful and imaginative 12th-century Historia Regum Britanniae (History of the Kings of Britain). Some Welsh and Breton tales and poems relating the story of Arthur date from earlier than this work; in these works, Arthur appears either as a great warrior defending Britain from human and supernatural enemies or as a magical figure of folklore, sometimes associated with the Welsh Otherworld, Annwn. How much of Geoffrey's Historia (completed in 1138) was adapted from such earlier sources, rather than invented by Geoffrey himself, is unknown.