conquest of the island, completed by October 30. September 5 – King George I of Great Britain issues the "Proclamation for Suppressing of Pirates in the West Indies", an offer of amnesty to pirates, declaring that any pirates who surrender themselves to the government of Britain or one of its overseas territories, on or before September 5, 1718, "shall have Our Gracious Pardon of and for his or their Piracy or Piracies" committed before January 5, 1718. The amnesty is later extended to July 1, 1719. September 21 – The first known Druid revival ceremony is held by John Toland at Primrose Hill, in London, at the Autumnal Equinox, to found the Mother Grove, what will later become the Ancient Order of Druids. September 29 – Guatemala earthquake: A 7.4 magnitude earthquake strikes Antigua Guatemala, destroying much of the city, and making authorities consider moving the capital of Guatemala to a different location. October–December October 9 – King Philip V of Spain orders the closure of all universities in Catalonia, including the historic Estudi General de Lleida. October 16 – Antonio Vivaldi's opera Tieteberga is performed for the first time, premiering at the Teatro San Moisè in Venice October 18 – Trial begins in Boston for six pirates who had survived the April 26 wreck of Samuel Bellamy's ships Whydah and the Mary Anne. Five of them (John Brown, Hendrick Quintor, Thomas Baker, Peter Cornelius Hoof and John Shuan) are convicted on October 22 of piracy and robbery and hanged on November 15. October 30 – The Spanish conquest of Sardinia, at this time part of the Holy Roman Empire, is finished two months after Spanish forces had landed on the island on August 22, as the last Sardinian outpost, Castelsardo, surrenders. November 28 – Pirates led by Edward Teach, more popularly referred to as "Blackbeard", and Benjamin Hornigold capture the French slave transport Concorde near island of Saint Vincent the West Indies. Blackbeard renames the vessel Queen Anne's Revenge, adds to its armaments, and makes it his flagship. Hornigold soon accepts a British amnesty for all pirates, and Blackbeard teams up with Stede Bonnet and begins plundering ships approaching North American ports. December 9 (November 29, O.S.) – King George I of Great Britain banishes his son and daughter-in-law, George, Prince of Wales and Caroline of Ansbach, from the royal household after the Prince threatens the King's personal assistant,