Question: "The Homecoming of Beorhtnoth Beorhthelm's Son" takes place during the aftermath of a battle that took place beside what river?

Context paragraphs:
Battle of Maldon: The Battle of Maldon took place on 10 or 11 August 991 CE near Maldon beside the River Blackwater in Essex, England, during the reign of Æthelred the Unready.  Earl Byrhtnoth and his thegns led the English against a Viking invasion.  The battle ended in an Anglo-Saxon defeat.  After the battle Archbishop Sigeric of Canterbury and the aldermen of the south-western provinces advised King Æthelred to buy off the Vikings rather than continue the armed struggle.  The result was a payment of 10,000 Roman pounds (3,300 kg) of silver, the first example of Danegeld in England.

Oxford Fashion Week: Oxford Fashion Week was established in 2009.  The event is now an annual fashion feature and takes place primarily over the course of one week in the year, with satellite events at other times.  In 2009 and 2010, Oxford Fashion Week took place in May.  In 2011, it took place in March.  In 2012, it took place in November.  Since 2013, the Oxford fashion week is taking place biannually displaying summer collections in March and autumn collections in September.

NBL Canada All-Star Game: The NBL Canada All-Star Game is an exhibition game hosted by the National Basketball League of Canada (NBL), currently matching a group of players from the Central Division against a group from the Atlantic Division.  The first All-Star game took place at the Halifax Metro Centre in Halifax, Nova Scotia on April 1, 2012.  In the inaugural game, the format did not take divisions into account and randomly divided players under captains Joey Haywood and Eddie Smith.  As of 2014, the players are decided on the coaches' votes.  No All-Star game took place for the 2014–15 NBL Canada season.  The game takes place alongside multiple other competitions, together known as All-Star Weekend.  These competitions include the Three-Point Long Distance Shootout and the Slam Dunk Championship.  Neither event took place in 2015.

Ender in Exile: Ender in Exile is a science fiction novel by Orson Scott Card, part of the "Ender's Game" series, published on November 11, 2008.  It takes place between the two award-winning novels: "Ender's Game" and "Speaker for the Dead".  It could also be considered a parallel novel to the first three sequels in the Shadow Saga, since the entirety of this "trilogy" takes place in the span of "Ender in Exile".  The novel concludes a dangling story line of the Shadow Saga, while it makes several references to events that take place during the Shadow Saga.  From yet another perspective, the novel expands (or "replaces") the last chapter of the original novel "Ender's Game".  On the one hand, it fills the gap right before the last chapter, and on the other hand, it fills the gap between the last chapter and the original (first) sequel (both named "Speaker for the Dead").  "Ender in Exile" begins one year after Ender has won the bugger war, and begins with the short story "Ender's Homecoming" from Card's webzine Intergalactic Medicine Show.  Other short stories that were published elsewhere are included as chapters of the novel.

Rhein in Flammen: Rhein in Flammen (English: "Rhine in Flames") is the name of five different firework displays along the river Rhine in Germany.  The displays take place annually, at various locations along the river.  On the five different dates, brightly illuminated ships sail the river in an evening convoy for their passengers to see the full firework display at each location of the river.  The firework displays are started when the ships arrive.  During the firework displays in St. Goar and St. Goarshausen, the convoy waits statically between the two castles Burg Maus and Burg Rheinfels.  On the river banks wine festivals take place that attract hundreds of thousands of visitors every year.  The biggest "Rhein in Flammen" event takes place in Koblenz every year, on the second Saturday in August.  The Bonn event takes place at the Rheinauen Park in Bonn, on the first Saturday in May.

Aeolian Tower: The Aeolian Tower was an art installation on the South Bank of the River Thames in London, consisting of a 15 m steel tower covered in 1200 wind-powered LEDs.  It was in place beside the Waterloo Bridge for three days, 14–16 November 2008.

Battle of Kuwait International Airport: The Battle of Kuwait International Airport occurred on February 27, 1991 during the 1st Gulf War.  It was a tank battle between the United States and Ba'athist Iraq.  Despite being a very large battle it is often overlooked compared to the other battles which took place during the war.  No less than elements of 18 divisions total participated in this battle.  U.S. Army Special Forces units and multiple Iraqi Commando units were also in theatre.  In reality the battle took place over a span of three days despite the primary battle at Kuwait International Airport lasting only one day.  Much of the combat actually took place en route to the airport.  The battle featured the "Reveille Engagement" which went on to become the biggest and fastest tank battle in United States Marine Corps' entire history.

The Homecoming of Beorhtnoth Beorhthelm's Son: The Homecoming of Beorhtnoth Beorhthelm's Son is the title of a work by J. R. R. Tolkien that was originally published in 1953 in volume 6 of the scholarly journal "Essays and Studies by Members of the English Association", and later republished in 1966 in "The Tolkien Reader".  It is a work of historical fiction, inspired by the Old English poem "The Battle of Maldon".  It is written in the form of an alliterative poem, but is also a play, being mainly a dialogue between two characters in the aftermath of the Battle of Maldon.  The work was accompanied by two essays, also by Tolkien, one before and one after the main work.

Lleida Latin-American Film Festival: The Lleida Latin-American Film Festival (Catalan: "Mostra de Cinema Llatinoamericà de Lleida" , or shortened to Catalan: "Mostra de Lleida" ) is a cinema festival that takes place in Lleida, Catalonia, Spain awarding Latin American films.  It is organised by the Latin American Centre of Lleida and is sponsored by the city council (La Paeria), the University of Lleida and La Caixa.  It's one of the main yearly cultural events in the town and takes place at the Teatre Principal, CaixaFòrum Lleida, Funatic, Cafè del Teatre de l'Escorxador, Institut d'Estudis Ilerdencs, the main campus of the University of Lleida, and the Hotel Condes de Urgel, alongside other cultural activities.  The event has taken place since 1995, and awards were first given in 1997.  At one time the festival took place in January but today it takes place in late March.

Los Cabos International Film Festival: Founded in 2012 by Scott Cross, Sean Cross, Eduardo Sanchez-Navarro Redo, Alfonso Pasquel, Juan Gallardo Thurlow, Eduardo Sanchez-Navarro Rivera Torres, and Pablo Sanchez-Navarro, the Los Cabos International Film Festival is an international film festival that takes place annually in mid-November in Los Cabos, Mexico.  The 2012 Los Cabos International Film Festival (formerly Baja International Film Festival) took place November 14–17 in Los Cabos, Mexico.  The 2013 Los Cabos International Film Festival took place November 13–16 in Cabo San Lucas, Mexico.  The 2014 Los Cabos International Film Festival took place November 12–16, 2014 in Los Cabos, Mexico.  The 2015 Los Cabos International Film Festival took place November 11–15, 2015 in Los Cabos, Mexico.  The 2016 Los Cabos International Film Festival took place November 9–13, 2016 in Los Cabos, Mexico.  The 2017 festival will take place November 8-12, 2017.  Held in one of Mexico's premier resort destinations, the festival draws attendees and filmmakers from across Mexico, the United States and around the world.

Supporting paragraphs: The Homecoming of Beorhtnoth Beorhthelm's Son Battle of Maldon
Answer: River Blackwater