Lonazep is a castle near Joyous Gard whose tournament turns a royal gathering into a test of allegiance and knightly standing. Summoned by King Arthur after Sir Tristram and La Beale Isoud reach the safety of Sir Launcelot’s castle, the event assembles rulers and knights from across the region. Its crowded field becomes the setting for a revealing reversal: the disguised Tristram and his companions overwhelm Arthur’s knights, until Sir Launcelot rides against Tristram and Arthur takes the field himself.

Setting and the Tournament’s Occasion

After escaping King Mark, Sir Tristram and La Beale Isoud are welcomed at Joyous Gard, Sir Launcelot’s castle, which is furnished to receive them in royal style. Launcelot tells Queen Guenever that Tristram has arrived with Isoud despite Mark, and Guenever relays the news to King Arthur. Arthur responds by proclaiming a tournament for May Day at Lonazep, described as close by Joyous Gard.

The proclamation divides the proposed contest along regional lines. Knights from Arthur’s lands, Cornwall, and North Wales are to joust against those from Ireland, Scotland, the rest of Wales, Gore, Surluse, Listinoise, Northumberland, and other territories owing allegiance to Arthur. Launcelot warns that the gathering puts the knights around the king in danger: many opponents envy them, and the day’s encounters may be severe. Arthur accepts that risk, treating the tournament as an occasion to discover who will prove best in arms. Launcelot, meanwhile, arranges a discreet place from which Isoud can watch.

The Gathering at Lonazep

The approach to the castle makes the tournament’s scale unmistakable. Sir Tristram, Sir Palamides, and Sir Dinadan see four hundred tents and pavilions and a great array of preparations. Their conversation sets this gathering against earlier tournaments, including the seven-day tournament at Surluse; Sir Dinadan recalls Sir Launcelot and Sir Lamorak as its leading knights. The comparison also brings Lamorak’s death into the present: Tristram mourns him and condemns the fact that Sir Gawaine and his brothers killed him in secret.

As the participants assemble, the contest is not merely a sporting fixture. At Lonazep, a horn summons those who will oppose King Arthur, and the rulers of Ireland, Surluse, Listinoise, Northumberland, and much of Wales gather to decide their arrangements. Sir Tristram hears King Marhalt of Ireland advise each king to use a separate banner and device, so that knights can rally to their own ruler and receive help from their own company. Tristram listens to this counsel before riding to hear Arthur’s side. The field is thus organized around competing standards and loyalties, even as individual knights retain room to choose their course.

Hidden Identities and Shifting Allegiance

The green-clad knights make their mark before Arthur knows who they are. Sir Palamides, riding a white horse, asks Tristram’s leave to encounter four knights: Sir Gawaine, Sir Uwaine, Sir Sagramore le Desirous, and Sir Dodinas le Savage. Tristram agrees and promises to help preserve Palamides’ honour. Palamides unhorses all four in succession, then Tristram continues toward Lonazep. The defeated knights wonder who the green company are; Gawaine suspects that the rider on the white horse may be Tristram or Palamides, and recognizes the lady accompanying them as Queen Isoud.

At Lonazep, Tristram and Dinadan hear the opposing kings’ council. Tristram then visits Arthur, who asks his name. Tristram declines to disclose it, on the condition that Arthur not press him for it, and says he has not yet decided which side he will join. He will choose when he reaches the field, according to where his heart leads, and promises that the next day will show his decision. The refusal leaves the tournament’s central uncertainty open: the man whose prowess has already been reported is present, but his identity and allegiance remain deliberately unsettled.

Combat and the Contest’s Reversal

On the following day, Tristram’s company appears in green. Before the fighting is fully underway, Gawaine and Sir Galihodin tell Arthur that the green knight on the white horse has already unhorsed them and six companions. Arthur summons Tristram, but he again withholds his name. He also refuses to promise in advance which side he will support, repeating that his choice will become clear in the field.

The scale of the reversals grows as the fighting proceeds. Heralds and onlookers report the green knight’s success against the men of Orkney. The heralds count twenty knights unhorsed by Tristram, now riding a black horse, and twenty by Palamides; most of the fifty knights defeated in the larger contest belong to Arthur’s household and are experienced fighters. The knights of Orkney tire of Tristram’s continued feats and withdraw to Lonazep. Rather than allowing the result to stand, Arthur decides to enter the contest. Sir Launcelot advises caution, noting that the opposing knights have already been heavily tested, but Arthur insists on answering the challenge.

Arthur, Launcelot, Sir Bleoberis, and Sir Ector ride out together and agree on their opponents. Launcelot chooses Tristram, Bleoberis is assigned Palamides, Ector is to meet Sir Gareth, and Arthur takes the green knight on the dappled horse, Sir Dinadan. Launcelot’s encounter with Tristram sharply reverses the day’s momentum: Launcelot strikes him with enough force to carry horse and rider down. The episode establishes Lonazep as more than a tournament venue. Its field exposes concealed identities and divided loyalties, measures the standing of Arthur’s knights against formidable visitors, and draws Arthur himself from royal observer into the contest.