Shortly after the year 900, men started to think about putting together a general assembly for the settlers of Iceland. The foundation of the Icelandic parliament is said to be the founding of the nation of Iceland, and the first parliamentary proceedings in the summer of 930 laid ground for a common cultural heritage and national identity. The Althing at Thingvellir was Iceland's supreme legislative and judicial authority from its establishment in 930 until 1262.
Logberg (Law Rock) was the focal point of the Althing and a natural platform for holding speeches. The Inauguration and dissolution of the assembly took place at the Logberg, where rulings made by the Law Council were announced, the calendar was confirmed, legal actions were brought and other announcements made which concerned the entire nation. Anyone attending the assembly was entitled to present his case on important issues from the Logberg.
The Althing was Iceland's legislative and chief judicial authority for the duration of the Commonwealth, until 1262. Executive power was in the hands of the chieftains and parties to individual cases at each time. This proved to be quite an adequate arrangement for as long as the balance of power remained, but flaws emerged when it was disrupted. The final decades of the Commonwealth were characterized by clashes between chieftain families, which resulted in Iceland becoming part of the Norwegian crown. Executive power was strengthened under this new order, while legislative and judicial authority remained in the hands of the Althing but was gradually transferred to the Norwegian and later Danish rulers until the King of Denmark became an absolute monarch of Iceland in 1662.
The assembly lasted for 2 weeks every summer and people had to travel for days to attend the Althing and well over 5000 people usually participated in the gathering.
Thingvellir was the center of Icelandic culture. Every year during the Commonwealth period, people would flock to Thingvellir from all over the country, sometimes numbering in the thousands. They set up dwellings with walls of turf and rock and temporary roofing and stayed in them for the two weeks of the assembly. Although the duties of the assembly were the real reason for going there, ordinary people gathered at Thingvellir for a wide variety of reasons. Merchants, sword-sharpeners and tanners would sell their goods and services, clowns performed and ale-makers brewed drinks for the assembly guests. News was told from distant parts; games and feasts were held. Young people met to make their plans, no less than leading national figures and experts in law. Itinerant farmhands looked for work and vagrants begged. Thingvellir was a meeting place for everyone in Iceland, laying the foundation for the language and literature that have been a prominent part of people's lives right up to the present day.
In the year 999 or 1000, Iceland's legislative assembly was debating which religion they should practise: Norse paganism, or Christianity. Lawspeaker Thorgeir Ljosvetningagodi, himself a pagan priest and leader, decided in favour of Christianity after a day and a night of silent meditation under a fur blanket. Pagans could still practise their religion in private. After his decision, Thorgeir himself became a Christian and threw the idols of his gods in a waterfall, for which that waterfall is now known in Icelandic as Godafoss, the "waterfall of the gods."
There has been a church at the site of Thingvellir since the introduction of Christianity but the church that stands there now was built in 1859.
Oxara river has been a prominent feature of Thingvellir ever since the assemblies began there. The river was diverted into Almannagja rift to give people at the assembly easy access to fresh water. Flooding from Oxara, combined with land subsidence, made it necessary to move the Law Council from its original location.
Thingvellir was an important symbol of national unity in Iceland’s process towards independence in the 19th and 20th centuries. The last Althing was held at Thingvellir in the summer of 1798. After the assembly was suspended, Thingvellir was a quiet place for a period of time.
When the European movement for independence reached Iceland at the beginning of the 19th century, the sagas and the landscape of Thingvellir were revitalized. Thingvellir then played a dominant role in society as a symbol of independence.
The reawakening of nationalism resulted in much discussion about the location of the new Althing. There were differences of opinion as to where the Althing should be located, but Thingvellir was suggested immediately.
Because of the Thingvellir meetings and the movement for independence, Thingvellir re-established itself as the main meeting place for Icelanders, where they could meet and celebrate the biggest and most important events in the history of the nation.
In 1874, a national festival was held at Þingvellir to celebrate 1000 years of the settlement in Iceland. On this occasion, King Kristian IX presented Icelanders with their first constitution, according to which the Althing was granted limited legislative and financial powers. Many Icelanders went to Thingvellir to witness an event that marked a watershed in their campaign for independence.
In the summer of 1930, a large festival was held at Thingvellir to celebrate the Millennium of the Althing itself. The Althing festival was the first general celebration of Icelanders where a substantial proportion of the nation was present, about 30-40,000 people. The foundation of the Icelandic republic took place at Thingvellir on the 17th of June 1944, the birthday of one of its national heroes, Jon Sigurdsson. Election for presidency took place at Logberg, and state leader Sveinn Bjornsson became the country's first president. At the end of the programme at Lögberg, the first cabinet meeting of the Republic took place, at which the President confirmed the law on the national flag and coat of arms.
In 1974, Icelanders celebrated the 1100th anniversary of the settlement. On 17th June 1994, a celebration was held at Thingvellir to mark 50 years since the foundation of the Icelandic republic.
In 1999, a festival to celebrate the Millennium of Christianity was set in motion. This included a series of events all over the country. The celebrations culminated in a two-day festival at Thingvellir in early June 2000.
Thingvellir is one of the most frequently visited tourist sites in the country. Each year, thousands of visitors go there to become better acquainted with Iceland's greatest historical site and jewel of nature.
Thingvellir was declared a national park in 1930. A law was passed designating Þingvellir as “a protected national shrine for all Icelanders, the perpetual property of the Icelandic nation under the preservation of parliament, never to be sold or mortgaged.”
Thingvellir were nominated to the World Heritage List on July 2, 2004. The nomination states that the site is of outstanding universal value and should be preserved as a cultural site and for its natural environment.
In the summer of 2000, two severe earthquakes occurred in South Iceland. Though their source lay 40-50 kilometres southeast of Thingvellir, stones fell from the ravine walls and water splashed up from the rifts. The earthquakes were a result of movement of the Eurasian and North American plate boundaries that run through Iceland. In the south, the plates inch past each other, but at Thingvellir, they break apart and the land between subsides. Away from the plate boundaries the activity is fairly constant, about two centimeters a year, but, in the rift zones themselves, tensional stress accumulates during a long period and is then released in a burst of activity when fracture boundaries are reached.
During the last glacial period, a layer of ice, more than a 1000 meters thick, covered the land. Despite the cold, there was widespread volcanic activity under the glacier. This activity formed tuffs. Some of these volcanic eruptions managed to melt through the glacial shield and ended in lava flows. Others melted only a cavity under the ice and formed palagonite mountains or long palagonite ridges.
When the temperature increased 18,000 years ago, the glacier began to melt and retreated gradually. The first indication of Lake Thingvallavatn appeared 12,000 years ago. The glacial tongue lay in the Thingvellir depression, and a glacial lagoon was formed to the south of it. Thingvallavatn lake was later formed when the glacier retreated to the north, and water from it accumulated in the depression. From beneath the glacier, various types of palagonite mountains that were formed by volcanic activity under the ice depression came to light. About 10,000 years ago, when the glacier had reached its current position, a shield volcanic eruption started. This resulted both in mount Skjaldbreidur one of the most beautiful shield volcanoes in Iceland, and a shield volcano south of mount Hrafnabjorg, from which the Thingvellir lava flowed. The eruption that formed the shield volcano probably lasted for decades, maybe even a century.
The lava collected murky glacial run-off water south of the Þingvellir depression. All the water from the north drained through the lava and reappeared below as clear spring water. The lava from the shield volcano south of Hrafnabjorg extended a long way into the lake and blocked off the outlet at Sogshorn. This meant that the water level rose, but at the same time it decreased considerably as lava occupied most of it. The lava flattened out over the Þingvellir depression, but land subsidence and rifting continued so the faults were renewed. You can now see a cross-section of the lava in the rift walls.
About 3000 years ago an 8 kilometre long eruptive fissure opened north-east of Hrafnabjorg and formed Þjofahraun. The lava spread out east of the Tindaskagi ridge but some ran north-west of Hrafnabjorg. The last eruption in the Thingvellir depression was 2000 years ago. That eruptive fissure is north-east of mount Hengill. The lava, Nesjahraun, ran into Grafningur and the ash crater Sandey arose from the bottom of Lake Thingvallavatn. Volcanic activity at Thingvellir has been dormant for 2000 years, but the question is not whether, but when it will start up again.
The lake Thingvallavatn is particularly fertile and rich in vegetation, despite the very cold temperatures. A third of the bottom area is covered by vegetation, and there is a large amount of algae. Low-growing vegetation extends out to a depth of 10 metres while higher vegetation forms a large growing-belt to 10-30 metres deep. A total of 150 types of plants have been found and 50 kinds of invertebrates, from the shore to the center.
In lake Thingvallavatn live three of the five species of freshwater fish found in Iceland: brown trout, Arctic charr and the three-spine stickleback. It's said that these fish became isolated in the lake in the wake of the last ice age when the terrain rose at the south end of Thingvallavatn.
Birch woodland is characteristic of the Thingvellir area. Birch, along with willow, plants of the heath family, and dwarf birch, transform the appearance of Þingvellir in autumn, and many make their way there to enjoy the beauty of its pastel colours.
Extreme Iceland offers tours to the Thingvellir National Park every day of the year.