The Summer of the Danes is a medieval mystery novel by Ellis Peters, set in 1144. It is the eighteenth in the Cadfael Chronicles and was first published in 1991.

Brother Cadfael is pleased to join his young friend Mark, now a deacon, on a mission of church diplomacy in Wales. Travelling in the safety of the Prince of Gwynedd's train, they are brought to unexpected dangers, as they seek to keep a young Welsh woman free from harm.

Introduction to plot The Anarchy is paused, except for the continued ravages of Geoffrey de Mandeville and his band of marauders in the Fens. Wales has a squabble between two brother princes, rooted in a murder the previous year. The Roman church under Theobald, the Archbishop of Canterbury, is extending its influence into Wales, which prefers its Celtic ways and the see of Saint David, by reviving an old bishopric straddling the border of England and Wales. Theobald requested that Bishop Roger de Clinton send a welcoming embassy to the new bishop, whose see includes parishes that once were under de Clinton.

Plot summary Three plots interlock in this novel. First is the embassy of Deacon Mark and Brother Cadfael to two bishops in Wales, reinforcing the Roman rite in Wales. Second is the young woman Heledd rejected by her canon father in reaction to imposition of the Roman rite, sending her to find love among historic Welsh enemies. Third is the trouble raised up by Cadwaladr, and resolved by Owain, who wanted no trouble with the Danes in their dragon boats.

Mark, a young deacon in the house of Roger de Clinton, Bishop of Lichfield and Coventry, is chosen to carry messages of good will to two bishops in Wales. He takes Brother Cadfael as translator into his homeland of north Wales in April 1144. They travel on horseback from Shrewsbury Abbey. Mark succeeds with the new bishop of Saint Asaph and the bishop of Bangor, sharing gifts and speaking as a diplomat. From Llanelwy to Bangor, they travel in the train of Owain Gwynedd, stopping at his royal seat at Aber overnight, where Cadfael finds a murdered man. Heledd rides away from Aber, not wanting to marry a man she has not chosen, awaiting her in Bangor.

Mark and Cadfael seek the lost Heledd as they head home. Cadfael finds her; as quickly as he does, the two are seized by a group of strong Danes led by Turcaill. They are prisoners in the camp of Otir, leader of the Danes of Dublin. Mark sees them and reports it to Owain. Heledd tells Cadfael she left Aber on a whim, finding the horse saddled and ready.

In a scheme to regain his lands and his good standing with his brother, Cadwaladr makes a deal with the Danes in Dublin to threaten Gwynedd. For Otir it is a cash transaction. The deal is for 2,000 marks in silver, cattle or goods. Otir's men are armed, but they have no plan to take on Owain's army. The ships land at Abermenai, opposite the island of Anglesey, at the end of the Menai Strait. Owain moves quickly to set up camp less than a mile away overnight. His brother approaches him with his scheme. Owain rejects it outright, telling his brother he must make good his debt to the Danes and keep the three captives safe. Cadwaladr instead tells the Danes that they should leave Gwynedd. Owain visits Otir to state his perspective on this awkward and potentially explosive situation. Cadwaladr will pay the amount he agreed, and the Danes will leave quietly.

Mark is the go-between to announce Owain's coming; he is left in place of Cadwaladr while the brothers talk in Owain's camp. Heledd relaxes in this break from her troubles by talking and teasing with Turcaill. Her unknown betrothed arrives at Owain's camp. Ieuan ap Ifor cannot wait; he plans a rescue in the night. Cadwaladr's supporters itch to release him so they join up with Ieuan. Upon hearing Owain's terms, Turcaill kidnaps Cadwaladr from Owain's camp in the night, so Otir can pressure Cadwaladr to gather his money and cattle to settle this affair.

Again Mark is the envoy, carrying Cadwaladr's words and seal to Owain, whom Cadwaladr trusts to gather his resources from his steward and bring them hence. Owain's son Hywel leads the party amassing the payment, Gwion riding out with them. The silver is loaded in barrels onto the Danish boats.

That night, Ieuan succeeds in seizing Heledd. Gwion, returned on his own with supporters of Cadwaladr, does not succeed in freeing him, but sparks a battle, which kills three of the Danes, and some of his own men. Owain arrives after dawn, with the drove of cattle finishing Cadwaladr's debt, seeing the Danes in full battle array. Gwion takes the moment to charge his own men again. Owain orders his men to stop. There are more casualties. Gwion takes a fatal wound from Otir. In the presence of Cadfael and Owain, Gwion confesses to the murder at Aber. His compatriot Bledri would not ride to Cadwaladr that night. The horse was gone. Cadwaladr received no intelligence, so the murder gained him nothing. His death is rough justice for the murder Gwion committed at Aber. Heledd accepts her capture by Ieuan equably. She approaches what had been Otir's camp. At sunset, Turcaill arrives in a boat. She leaves with the man of her choice, leaving behind her troubles with her father.

Mark and Cadfael proceed to Shrewsbury Abbey. They stay at Hugh's manor in Maesbury overnight for a pleasant family visit, with Aline and young Giles to cheer them. They overstayed the ten days promised to Abbot Radulfus, and Cadfael is happy to go home.

Characters Brother Cadfael: Herbalist monk and sometime sleuth at Shrewsbury Abbey, born in Wales. He is aged about 64 in this story. In dialogue with Mark or Cuhelyn he tells his own Welsh heritage and his decisions in youth to leave Wales when he was offered the chance to travel to Shrewsbury at the age of 14. His life has now travelled a full circle; he is pleased to be tied to a small piece of land and a small fraternity of brother monks. Abbot Radulfus: Head of the Benedictine Abbey of Saint Peter and Saint Paul, based on the real abbot of the era. He released Cadfael to aid Mark. Hugh Beringar: Sheriff of Shropshire, appointed by King Stephen. He owns manors at Maesbury, near the border with north Wales. From both his home location and his agreements as Sheriff with Owain and other neighbouring rulers, he advises Mark on his best route, and some delicate points in present politics. Introduced in One Corpse Too Many. Deacon Mark: Deacon with Bishop Roger de Clinton sent on embassy to two parishes in Wales. As a young monk, he spent two years with Cadfael, where they became great friends. He has a talent for reading people's true natures and true needs. His priestly studies are financed by Leoric Aspley (see The Devil's Novice). About 23 years old. Officially introduced in Monk's Hood, but he may have been unofficially mentioned at the very end of A Morbid Taste for Bones. Bishop Gilbert: He is newly appointed by Theobald, Archbishop of Canterbury to head the revived diocese of Saint Asaph at Llanelwy, its parishes straddling the boundary of Wales and England, and formerly in the see of Bishop Roger de Clinton. A man of Norman birth, he speaks no Welsh. Real historical bishop. Bishop Meurig: Welsh bishop of Bangor. He swore allegiance to King Stephen, accepted Canterbury as the only Archbishop four years earlier. He is a pleasant and practical man. Real historical bishop. Owain Gwynedd: Prince of Gwynedd. He is a real historical person, who is in his early forties in this story. He is attempting to unite the independent parts of Wales through dynastic marriages and strategic alliances. He was mightily displeased with his brother Cadwaladr for directing the murder of the Prince of Deheubarth, who was betrothed to Owain's daughter, and dispossessed Cadwaladr of his lands. This prince makes his second appearance as a character in this series of novels. Hywel ab Owain: Second son of Owain, who drove Cadwaladr out of his lands on his father's order. Also a poet. He is about 20 years old. Real historical person. Rhun ab Owain: Eldest son of Owain. He has his father's appearance, is the pattern of a prince since age 16, and his father's favourite. Real historical person. Cadwaladr: A younger brother of Owain. He was dispossessed of his lands in north Ceredigion in Wales by Owain for his role in killing Prince Anarawd of Deheubarth. He escaped to Ireland in disgrace. He is a strong man, with an impetuous temper. He is a real historical person who made such troubles in history. Anarawd ap Gruffydd: Prince of Deheubarth in southern Wales. He was an ally to Owain Gwynedd and betrothed to his daughter; then slain by Cadwaladr's men in the year before the story started. His death is the reason for Owain stripping Cadwaladr's lands from him. Real historical person. Canon Meirion: Canon of the new see at Saint Asaph, under Bishop Gilbert. He was a married priest who is now widowed, father of Heledd. He is balancing his career against his daughter, under the new rules. The depth of his feelings for her shows itself when she runs away. Heledd: Bold, observant, beautiful dark-haired daughter of Meirion. She is betrothed to a man she has never met, feeling unloved by her father. Her mother died the prior Christmas, an event awaited by the Bishop Gilbert. She is 17 or 18 years old. Wales kept married priests, but the Roman rite so recently imposed disallows them. The new bishop finds her a bad sign of old sinful ways. Canon Morgant: Another canon under Bishop Gilbert. He is sent with the party bringing Heledd to meet her betrothed in Bangor. Cuhelyn ab Einion: Warrior seriously injured in serving Prince Anarawd the prior year. He lost his left hand in that encounter. He is now in the household of Owain Gwynedd. Mark notices the resemblance between Cuhelyn and Gwion, in looks and passion, though mirror images in Cadfael's view. At the meal with Bishop Gilbert, Cuhelyn recognises Bledri ap Rhys as one of the eight in the party who attacked him and Prince Anarawd. Bledri ap Rhys: Man in Cadwaladr's service. He was of the group who murdered Prince Anarawd. He is an unexpected envoy at a meal at Saint Asaph at Llanelwy to all but the new bishop, who wants Owain to reconcile with his brother. He travels with the party leaving Llanelwy the next day. He was found murdered the next morning at Aber. Gwion: Young man at Aber on his parole for the last six months. Hostage from among the lesser chiefs of Cadwaladr, fiercely loyal to him, and unwilling to "promise peace" to Hywel. He and Bledri ap Rhys are of the same allegiance. He is seen speaking with Bledri in the chapel after the feast. Ieuan ab Ifor: Betrothed chosen for Heledd by Owain. He is present with Owain's army at Carnarvon; of Anglesey. He is in his mid-thirties, grey already salting his dark hair, of muscular build. Turcaill son of Turcaill: One of the Danes from Dublin aligned with Cadwaladr. He seized Heledd and Cadfael. He is a tall, strong, flaxen-haired young man. Leif: Son of a Welsh mother and Danish father, who speaks Welsh like a native. At 15 years old, he spies among the Welsh for Turcaill. Otir: Leader of the Danes of Dublin. He is allied with Cadwaladr in his fight to regain his lands in Wales from his brother Owain. This is a transaction for money gain, rather than a political alliance for Otir. Real historical person.

Continuity

Deacon Mark was first introduced by name in Monk's Hood as the assistant to Cadfael at the end of 1138. Cadfael has much respect for Mark, and is delighted he received a gift for his education to become a priest in The Devil's Novice two years later, a gift from the lord of a local manor whose son was helped by Brother Mark. In several later novels, Cadfael speaks of how he will wait to confess what he thinks his worst sins to Mark, when he is a priest, as Mark understands him so well. Serving Mark as a translator suits Cadfael well now, his favourite helper progressing so well on his way to priesthood.