In the first half of 13th century Schweinfurt was expanded to a real city with city wall, towers and city gates. At that time the Nikolaus hospital was founded, a mint was established and construction work on the Saint Johannis church began.
Around 1250 Schweinfurt was totally destroyed during a feud between the Earl of Henneberg and the Prince-Bishop of Würzburg. In the following years it was reconstructed. A document from 1282 signed by King Rudolf I of Habsburg states that Schweinfurt was a free city within the Holy Roman Empire. At least since then the known coat of arms of Schweinfurt is an imperial white eagle. In 1309 the city was given to the Count of Henneberg, but in the 1360s the city regained its independence and joined the Swabian–Franconian Confederation. In 1397 King Wenzel entitled the town to utilize the river Main, and in 1436–37 Schweinfurt acquired the village of Oberndorf, as well as the Teutonic Order Fort on the Peterstirn and a small piece of land-including the villages of Zell and Weipoltshausen. Some years later there was the first uprising of Schweinfurt's people against the town council, followed by a second one in 1513–14. This time the issuing of a constitution was allowed.
The city joined the Martin Luther's Reformation in 1542. Schweinfurt was again destroyed in the course of the Margravian War, in 1554. The years up to 1615 were spent by the citizens for its reconstruction.
Schweinfurt joined the Protestant Union in 1609. In the Thirty Years' War it was occupied by Gustavus Adolphus, who erected fortifications, remains of which are still extant. In 1652 the four doctors Johann Laurentius Bausch, Johann Michael Fehr, Georg Balthasar Wolfahrt and Balthasar Metzger founded the Academia Curiosorum in Schweinfurt, which is known today as the German Academy of Life Scientists, "Leopoldina".
At some point the inhabitants were reverted to catholicism, only to again receive a large section of Lutheran refugees/expellees after 1945 from Germany east of the Oder-Neisse line. The latest addition to the Lutheran churches in Schweinfurt arrived during the last years of the Soviet Union.
In 1777 Johann Martin Schmidt commenced with the production of white lead (ceruse). Schweinfurt suffered from heavy casualties during the Napoleonic Wars of 1796-1801.
Schweinfurt remained a free imperial city until 1802, when it passed to the Electorate of Bavaria. Assigned to the grand duke of Würzburg in 1810, it was granted to the Kingdom of Bavaria four years later. The first railway junction was opened in 1852. In the following years Schweinfurt became a world leader centre for the production of ball bearings. This was to lead to grievous consequences for the city during World War II.
Schweinfurt was the location of most of the ball-bearing production in Nazi Germany at the onset of World War II, and was eventually devastated following a series of Allied strategic bombing raids. It was hoped that the destruction of the factories located in the city would cripple the production of new tanks and aircraft.
Two of these raids, the Schweinfurt-Regensburg mission and the Second Raid on Schweinfurt, were particularly costly for the United States Army Air Forces. On August 17 1943, 230 B-17s of the USAAF 8th Air Force, intended as the second wave of bombers behind a force attacking Regensburg, encountered intense anti-aircraft artillery and over 300 defending fighter aircraft, with the result that only 184 aircraft bombed their targets and 36 aircraft did not return to their bases in England. Production suffered an immediate 34% cutback, and all plants but the largest were devastated by fire, but the existing industrial infrastructure had not been conducive to destruction by a single raid. Efforts to disperse the surviving machinery began immediately and the Luftwaffe, recognizing the threat, began redeploying large numbers of interceptors along the corridor to Schweinfurt.
After rebuilding its strength the 8th Air Force mounted a second attack on October 14, 1943, which proved to be more costly than the first and became known as "Black Thursday". In this raid by 291 B-17s, 229 bombed the target and 60 were lost. Such very heavy losses could not be sustained, and unescorted bomber raids deep into Germany were suspended until 1944. Raids on Schweinfurt resumed in February, 1944 during what came to be known as "Big Week."
Although losses of production bearings and machinery were high, and much of the industrial and residential areas of the city were destroyed, killing more than a thousand civilians, the factories were restored to production and the industry dispersed. Although German planners initially thought it essential to purchase the entire output of the Swedish ball-bearing industry, losses in production bearings were actually made up from surpluses found within Germany in the aftermath of the first raid.
The Allies, according to Albert Speer, were remiss in not mounting a decisive bombing campaign against the bearing industry while it was still centrally located. Once de-centralized, the Nazis were able to rebuild output to 85% of its pre-bombing output. Hitler made restoration of ball-bearing production a high priority, and massive efforts were undertaken to repair and rebuild the factories partially in bomb-proof underground facilities Schweinfurt was bombed 22 times by the USAAF and RAF, by a total of 2285 aircraft, until it was captured by the 42nd Infantry Division in house-to-house fighting in April 1945.
The Schweinfurter Rathaus (town hall) square has a large Friedrich Rückert monument in the center around which weekly markets and many city festivals are held. A large number of immigrants from many other countries add to the crowded innercity traffic-free Markthalle shopping area.
Motherwell Park connects the surrounding medival buildings to the innercity market square. To avoid car-filled streets, walking through the park with part of the original city walls, offers pathways and shortcuts bringing one on foot from one end of town to another, reminiscent of medival town life.