The interest in medieval sword fighting is so widespread among members that “there’s a different place to practice every night in the New York area,” said Zach Karabin, 29, of Bensonhurst, Brooklyn, who works as a union glazier in Manhattan but on weekends dominates battlefields as Ozurr the Bootgiver, a fierce Viking warrior.

Many fighters spend years striving to become knights through battlefield valor and acts of chivalry. Some compete to capture the crown, a position with a six-month tenure attained by winning a special armored combat tournament.

While it is often a man fighting for his female “consort” to join him on the throne, women have also competed for the crown, as have same-sex couples.

Mr. Karabin won a series of sword-and-shield fights recently to become the next ruler of the East Kingdom; his reign begins in April .

For now, he is still the kingdom’s prince. And at the 100 Minutes War, he wore his princely crown, while the king and queen wore their gold-plated crowns, all of which are passed down within the society, which was founded by a group of history buffs and writers in Northern California in the mid-1960s.

Within the group, “there’s a sense of community that is lacking in society today,” said Mr. Van Ostenbridge, who met his wife at a Twelfth Night celebration in Kingston, N.Y.

Mr. Van Ostenbridge, an engineer for a technology firm and former Marine, said members shared a common background. “We were all nerds growing up,” he said. But they were also a diverse group.