After finishing the Coq Rouge series, Guillou wrote a trilogy about Arn Magnusson, a 12:th century Folkung who was forced to become a Knight Templar. The series is an account of the life of Arn, a person who becomes witness as well as catalyst to many important historical events, both in his homeland of Götaland, Sweden and in the crusader states.
The trilogy consists of the following novels:
- The Road to Jerusalem, originally Vägen till Jerusalem (1998)
- The Knight Templar, originally Tempelriddaren (1999)
- The Kingdom at the End of the Road, originally Riket vid vägens slut (2000), also called Birth of a Kingdom
Two films based on the books have been produced. The first film in the series, Arn – The Knight Templar, premiered in the theaters of Sweden in Christmas 2007. Its plot loosely follows the first two volumes of the trilogy. The second film, Arn – The Kingdom at Road's End, followed in 2008.
Arn was born in Arnäs, Västergötland in 1150. At the age of 5, he had a life-threatening accident, and was believed to be saved thanks to his mother's prayers to Saint Bernard of Clairvaux. Since the boy was saved, his parents decided that in recompensation for the miracle, he was to be sent to a monastery. He spent the next twelve years of his life in the monastery Varnhem in Sweden.
He met brother Guilbert, a former Knight Templar, who instructed him in the use of the sword and the art of medieval war being used in the Holy Lands. The Prior, Father Henri, told Arn to witness for himself the outside world, and only after that he would be able to take the eternal vows of poverty, chastity and obedience (q.v. Evangelical counsels). Arn did so, but committed the terrible sin of fornication with Cecelia Algotsdotter, before they had been married (although they were engaged). Cecelia became pregnant and told her sister Katarina what happened between Arn and herself. Katarina, who would now become stuck in the nunnery where they each had spent half their time up till know, became jealous and found a plan for her to get out instead of her sister. Katarina thus told the Abbess that Cecelia had sinned with Arn, and was with child. Further she told, truthfully, about the fact that Arn also had carnal knowledge of her as well, from a party at her parents where a very young and drunk Arn had been seduced. According to the laws of the Church, it was considered especially heinous and scandalous to have sexual intercourse with two women who had the same mother (comparing it to having sex with your own daughter). Arn was condemned to spend 20 years in the Holy Land as a Knight Templar, while Cecelia was kept in the nunnery, and her newborn child taken away from her.
At the age of 27, Arn is already a veteran in the Crusader army, when he faces the strangest experience a Knight Templar can have. During a time of truce, while pursuing a band of Saracen thieves, he comes across the very enemy of all Christendom, Saladin, and saves his life. This idea is apparently borrowed from The Talisman by Sir Walter Scott. After this, both become very close friends, but great enemies at the same time. Arn returns to his command of the fortress at Gaza, later seeing Saladin's army arrive but not stay to lay siege, instead advancing on a bigger prize, the city of Jerusalem. Arn is given the order to march with all his knights, and they defeat Saladin's army at the Battle of Montgisard. When Arnold of Torroja is named Grand Master of the Knights Templar, Arn is summoned to Jerusalem to become Master of the city.
In the Battle of Hattin, Arn is severely wounded and spends several weeks at Saladin's hospital in Damascus, after that he accompanies him to Jerusalem, which is conquered. In the very end of the second book, Richard the Lionheart comes to Palestine with an army of crusaders. He captures Acre from Saladin, and when about to buy the freedom of 5,700 prisoners from the Christian king, Saladin and Arn were horrified to see Richard having them slaughtered, even the children "as the mamluks were riding, trying to save them, in tears." Arn then confides that Richard "only will be remembered as the slaughterer" and that he will never capture Jerusalem, thus confiding himself that he doesn't care if the city remains in Muslim hands. He embraces Saladin, and then starts traveling home to Sweden, where a kingdom is about to be born. On his leave Saladin hands him a very large sum of gold money, the money that Richard declined to kill the prisoners. He also awards him a special sword worthy of a Knight Templar. The money allows him to fulfill the plans he has with the new kingdom.
After returning to Sweden along with a group of people from the Holy Land (among them two Armenian craftsmen, two Englishmen specializing in crossbows and longbows, glass workers, felt makers, copper smiths and two learned Saracen physicians), Arn has great plans for his childhood home, Arnäs, and Forsvik, the estate which was to be his before he was forced into service as a Templar. He explains his idea of "building for peace" by constructing a modern castle at Arnäs and to create a manufacturing centre at Forsvik.
When he returns to his family, they are at first overwhelmed with a joy that soon cools when he voices his desire to marry Cecilia. His family wishes to use him for a political marriage, but due to the intrigues of Cecilia and her friend the Queen they are soon after married, earning them the enmity of Birger Brosa. After a little time they have a daughter together and Forsvik grows rapidly.
However his newfound luck is shattered when King Sverker attempts to kill the sons of the late King Knut. Commanding his force of cavalry, he defeats the king's soldiers at the Battle of Älgarås. He also takes command at the Battle of Lena and emerges victorious.
Two years later, when King Sverker returns once again with a Danish army and Arn commands the forces of King Erik at the Battle of Gestilren. He takes a fatal wound while pushing forward to kill King Sverker, he succeeds in this and the battle is won. He dies of his wounds a few days later, now aged 60, and is buried in Varnhem monastery.
The Knight Templar trilogy is translated to the following languages:
- Bulgarian (Рицaрят тaмплиeр: "Пътят към Йeрусaлим", "Рицaр нa Хрaмa", "Крaлствo в крaя нa пътя")
- Catalan (Trilogia de les Croades: El camí de Jerusalem, El cavaller del Temple and El retorn a casa)
- Chinese (圣殿骑士)
- Croatian (Put u Jeruzalem, Vitez Templar, Kraljevstvo na kraju puta)
- Czech (Cesta do Jeruzaléma, Templářský rytíř, Království na konci cesty).
- Danish (Historien om Arn: Vejen til Jerusalem, Tempelridderen and Riget ved vejens ende, and besides that Arven efter Arn)
- Dutch (De weg naar Jeruzalem, De Tempelridder and De terugkeer)
- English (The Crusades Trilogy: The Road to Jerusalem, The Templar Knight, and Birth of the Kingdom)
- Estonian (Tee Jeruusalemma, Templirüütel and Riik tee lõpus)
- Finnish (Ristiretki-trilogia: Tie Jerusalemiin, Temppeliherra and Pohjoinen valtakunta and as fourth Arnin perintö)
- French (Le Chemin de Jérusalem - Trilogie d'Arn le templier - tome I, Le Chevalier du Temple - Trilogie d'Arn le templier - tome II, Le Royaume au bout du chemin - Trilogie d'Arn le templier - tome III, L'Héritage d'Arn le templier)
- German (Die Götaland-Trilogie: Die Frauen von Götaland, Die Büßerin von Gudhem and Die Krone von Götaland)
- Italian (Il Romanzo delle Crociate: Il Templare, Il Saladino, La Badessa)
- Norwegian (Arn-trilogien: Veien til Jerusalem, Tempelridderen and Riket ved veiens ende, and besides that Arven etter Arn)
- Polish (Krzyżowcy: Droga do Jerozolimy, Rycerz zakonu templariuszy, Królestwo na końcu drogi)
- Portuguese (Trilogia "As Cruzadas": A Caminho de Jerusalem, O Cavaleiro Templário and O Novo Reino)
- Serbian (Витез темплар: Пут за Јерусалим, Темплар, and Краљевство на крају пута)
- Spanish (El camino a Jerusalén, El caballero templario and El reino al final del camino/Regreso al Norte)
- The Road to Jerusalem (1998), ISBN 91-1-300565-0 the first book in the series
- The Knight Templar (1999), ISBN 91-1-300733-5 the second book in the series
- The Kingdom at the End of the Road (2000), ISBN 91-89426-02-9 the third book in the series
- The Heritage of Arn (2001), ISBN 91-642-0003-5 sequel to the trilogy
- Sandra Ballif Straubhaar, "A Birth Certificate for Sweden, Packaged for Postmoderns: Jan Guillou's Templar Trilogy," in The Year's Work in Medievalism 15 (2002), ed. Jesse Swan and Richard Utz.