Battle of Grunwald
By the end of October only four Teutonic castles along the border remained in Polish hands. Władysław II Jagiełło raised a fresh army and dealt another defeat to the order in the Battle of Koronowo on 10 October 1410. Following other brief engagements, both sides agreed to negotiate.
The Peace of Thorn was signed in February 1411. Under its terms, the order ceded the Dobrin Land (Dobrzyń Land) to Poland and agreed to resign their claims to Samogitia during the lifetimes of Władysław II Jagiełło and Vytautas, although another two wars—the Hunger War of 1414 and the Gollub War of 1422—would be waged before the Treaty of Melno permanently resolved the territorial disputes. The Poles and Lithuanians were unable to translate the military victory into territorial or diplomatic gains. However, the Peace of Thorn imposed a heavy financial burden on the order from which they never recovered. They had to pay an indemnity in silver in four annual installments. To meet these payments, the order borrowed heavily, confiscated gold and silver from churches, and increased taxes. Two major Prussian cities, Danzig (Gdańsk) and Thorn (Toruń), revolted against the tax increases. The defeat at Grunwald left the Teutonic Order with few forces to defend their remaining territories. Since Samogitia became officially christened, as both Poland and Lithuania were for a long time, the order had difficulties recruiting new volunteer crusaders. The Grand Masters then needed to rely on mercenary troops, which proved an expensive drain on their already depleted budget. The internal conflicts, economic decline, and tax increases led to unrest and the foundation of the Prussian Confederation, or Alliance against Lordship, in 1441. This in turn led to a series of conflicts that culminated in the Thirteen Years' War (1454).

Battlefield memorials: Ideas about commemorating the battle rose right after the event. Władysław II Jagiełło wanted to build a monastery dedicated to Saint Bridget of Sweden, who had prophesied the downfall of the Teutonic Order, at the location of the battle. When the order regained the territory of the battlefield, the new grand master Heinrich von Plauen built a chapel dedicated to Saint Mary and it was consecrated in March 1413. It was destroyed by the Poles when they invaded during the Hunger War of 1414, but it was quickly rebuilt. The chapel fell to ruins during the Protestant Reformation and was demolished in 1720. Over time, the location of the chapel became associated with the location where Grand Master Ulrich von Jungingen was killed. In 1901, a large memorial stone was erected for the fallen Grand Master in the midst of the chapel ruins for the 200th anniversary of the coronation of King Frederick I of Prussia. The inscription was chiseled in 1960 and the stone was removed from the chapel ruins and placed inscription facing down in 1984.
In 1960, for the 550th anniversary, a museum and monuments were constructed a little northeast of the chapel ruins. The grounds were designed by sculptor Jerzy Bandura and architect Witold Cęckiewicz. The monuments included an obelisk of Silesian granite depicting two faces of knights, a bundle of eleven 30-metre (98 ft)-high flagpoles with emblems of the Polish–Lithuanian army, and a sculptural map depicting the supposed positions of the armies before the battle. Presumed locations where Władysław II Jagiełło and Vytautas had their main camps were marked with artificial mounds and flagpoles. The battle site is one of Poland's national Historical Monuments, as designated on 4 October 2010, and tracked by the National Institute of Cultural Heritage. The museum, which is open during summers, has an exhibition space of 275 square metres (2,960 sq ft) in which it displays archaeological finds from the battlefield, original and reproduced medieval weapons, reconstructed flags from the battle, as well as various maps, drawings, and documents related to the battle. In 2018, the museum was visited by about 140,000 people. Construction of a larger year-round museum at an estimated cost of 30 million Polish złoty (6.5 million euros) started in April 2019.
In July 2020, a large stone with engraved Vytis was erected by the Lithuanians near the monument site to commemorate the 610th anniversary of the battle. The monument was unveiled by Lithuanian and Polish presidents Gitanas Nausėda and Andrzej Duda.

Archaeological excavations: Several artifacts from the battlefield are known from historical record, for example stone balls in the church of Stębark (Tannenberg) and a metal helmet with holes in the church of Mielno which was gifted to Frederick William IV of Prussia when he visited the battlefield in 1842, but they have not survived to the present day. The first amateur archeological research was carried out in 1911 in hopes of finding the mass graves mentioned by Jan Długosz at the church of Stębark. The church was surveyed with ground-penetrating radar in 2013 but little evidence of the mass graves was found.
The first more thorough archaeological excavations of the battlefield were carried out in 1958–1960 in the run-up to the 550th anniversary, connected to the construction of the memorial site and museum. The government showed great interest in the excavations and sent helicopters and 160 soldiers to help. Research continued in later decades, but yielded very little results with the exception of the area around the ruined chapel. Several mass graves were found at the chapel: remains of six people in the vestibule, 30 people next to the southern wall, more than 130 people in three pits adjacent to the chapel, and about 90 people in the sacristy. Many remains showed signs of traumatic injuries. Some skeletons showed signs of being burned and moved. Mass burials, including of women and children, were also found in the villages of Gilgenburg (Dąbrówno) and Faulen (Ulnowo). The massacre in Gilgenburg was known from written sources, but the burial in Faulen was unexpected. In the fields, very few items of militaria were found. In 1958–1990, only 28 artefacts were found connected to the battle: ten crossbow bolts, five arrowheads, a javelin head, two sword pieces, two gun bullets, six pieces of gauntlets, and two small arms bullets. 
In 2009 Swedish historian Sven Ekdahl published his long-held hypothesis that the traditionally accepted location of the battlefield was incorrect.  He believed that the surveys near the chapel ruins were actually around the site of the Teutonic Order's camp.  According to Ekdahl's theory, the main battlefield was located northeast of the road between Grunwald and Łodwigowo, about 2 kilometres (1.2 mi) southwest of the memorial site.  Between 2014 and 2019, archaeologists from Scandinavia and Poland investigated an area of approximately 450 hectares (1,100 acres) with metal detectors and located the main battle site according to Ekdahl's predictions. In 2017, the team found approximately 65 crossbow bolts and 20 arrowheads, as well as parts of spurs, stirrups, gauntlets, etc.  As of 2020, archaeologists had discovered about 1,500 artifacts of which about 150 are linked to the battle. Among them are a Teutonic clasp to fasten coat with the Gothic inscription ‘Ave Maria’, a seal with the image of a pelican feeding its young with blood, two well preserved axes, and Teutonic coins.
The 2014-2019 surveys have been criticsed due to inconsistent publications and not following scientific techniques established by battlefield archeology.  These include preservation of findings, lack of survey maps and inconsistent recording of GPS data.  There has also been a lack of funding from the Polish government for reliable research of the entire battlefield.

Legacy: In William Urban's summary, almost all accounts of the battle made before the 1960s were more influenced by romantic legends and nationalistic propaganda than by fact. Historians have since made progress towards dispassionate scholarship and reconciliation of the various national accounts of the battle.

Poland and Lithuania: The Battle of Grunwald is regarded as one of the most important in the histories of Poland and Lithuania. In Lithuania, the victory is synonymous with the Grand Duchy's political and military peak. It was a source of national pride during the age of Romantic nationalism and inspired resistance to the Germanization and Russification policies of the German and Russian Empires. The Teutonic Order was portrayed as bloodthirsty invaders and Grunwald as a just victory achieved by a small, oppressed nation.
In 1910, to mark the 500th anniversary of the battle, a monument by Antoni Wiwulski was unveiled in Kraków during a three-day celebration attended by some 150,000 people. About 60 other towns and villages in Galicia also erected Grunwald monuments for the anniversary.