The settlement on the road leading from Magdeburg to Gniezno was first mentioned as Mezerici by the medieval chronicler Thietmar of Merseburg in the course of the 1005 campaign of King Henry II of Germany into the Polish lands of Duke Bolesław I Chrobry.
The Old Polish name Mezyriecze first appeared in the 1112/16 Gesta principum Polonorum by Gallus Anonymus.

It remained a western outpost of the Duchy of Greater Poland, established by the 1138 Testament of Bolesław III Krzywousty, after the loss of Lubusz Land in the mid-13th century and was incorporated into the Poznań Voivodeship of the Polish Crown upon the coronation of King Władysław I the Elbow-high in 1320.
Under the rule of his successor Casimir III the Great (1333–1370) German settlers began to migrate into the area in the course of the Ostsiedlung.
Town privileges were confirmed by King Casimir IV Jagiellon in 1485.
Międzyrzecz was a royal town of the Polish Crown and the seat of starosts (local royal administrators).
In 1520 it was ravaged by the Germans.

The town remained part of the Polish–Lithuanian Commonwealth until in the Second Partition of Poland of 1793 it was annexed together with the whole region of Greater Poland by the Kingdom of Prussia.
The town at first was part of the South Prussia province, was ceded to the Poznań Department of the Napoleonic Duchy of Warsaw by the 1807 Treaties of Tilsit, and upon the 1815 Congress of Vienna fell back to Prussia, administrated within the Grand Duchy of Posen.
In 1818 the town became the capital of the Prussian Kreis Meseritz within Regierungsbezirk Posen.
After the failed Greater Poland Uprising of 1848, it was incorporated into the Province of Posen, which, with Prussia, became part of the unified German Empire in 1871.
According to a 1900 census, 20.2% of the population were Polish native speakers.
The settlement on the road leading from Magdeburg to Gniezno was first mentioned as Mezerici by the medieval chronicler Thietmar of Merseburg in the course of the 1005 campaign of King Henry II of Germany into the Polish lands of Duke Bolesław I Chrobry. The Old Polish name Mezyriecze first appeared in the 1112/16 Gesta principum Polonorum by Gallus Anonymus.
It remained a western outpost of the Duchy of Greater Poland, established by the 1138 Testament of Bolesław III Krzywousty, after the loss of Lubusz Land in the mid-13th century and was incorporated into the Poznań Voivodeship of the Polish Crown upon the coronation of King Władysław I the Elbow-high in 1320. Under the rule of his successor Casimir III the Great (1333–1370) German settlers began to migrate into the area in the course of the Ostsiedlung. Town privileges were confirmed by King Casimir IV Jagiellon in 1485. Międzyrzecz was a royal town of the Polish Crown and the seat of starosts (local royal administrators). In 1520 it was ravaged by the Germans.
The town remained part of the Polish–Lithuanian Commonwealth until in the Second Partition of Poland of 1793 it was annexed together with the whole region of Greater Poland by the Kingdom of Prussia. The town at first was part of the South Prussia province, was ceded to the Poznań Department of the Napoleonic Duchy of Warsaw by the 1807 Treaties of Tilsit, and upon the 1815 Congress of Vienna fell back to Prussia, administrated within the Grand Duchy of Posen. In 1818 the town became the capital of the Prussian Kreis Meseritz within Regierungsbezirk Posen. After the failed Greater Poland Uprising of 1848, it was incorporated into the Province of Posen, which, with Prussia, became part of the unified German Empire in 1871. According to a 1900 census, 20.2% of the population were Polish native speakers.
Międzyrzecz