For 100 years the Viking settlers of Iceland happily co-existed with each other, worshipping Odin, Thor and Freya. By the 10th century, however, Catholicism had been introduced along with its concepts of sin and chastity. Tensions increased until civil war threatened. In 1000 the Alþing appointed one of the chieftains, Þorgeirr Ljósvetningagoði, to decide the issue of religion by arbitration. He decided that the country should convert to Christianity as a whole, but that pagans would be allowed to worship privately. Paganism eventually faded away and for the next 500 years Iceland was Catholic until that troublemaker Martin Luther came along. In 1550 the last opposition to the Reformation was put down when Jón Arason was defeated in the Battle of Sauðafell. For his efforts Arason and his two sons were beheaded and Iceland has been largely Lutheran ever since. Hallgrímskirkja (Church of Hallgrímur) is, at 73 meters (244 feet), the largest Lutheran church in Iceland. Commissioned in 1937, work began in 1945 and was finished in 1986. It was designed by State Architect Guðjón Samúelsson to resemble the basalt lava flows of Iceland's landscape. The statue of Leif Ericsson was a gift from the United States in 1930 to commemorate the 1000 year anniversary of Iceland's parliament at Þingvellir in 930 AD.