Aizpute (German: Hasenpoth; historically Polish: Hazenpot) is a town in South Kurzeme Municipality in the Courland region of Latvia, in the valley of the Tebra River, situated 50 km (31 mi) northeast of Liepāja.

In a cartographic drawing of Bandava, Aizpute is marked with the name Asseboten, in 13th century writings Asimpute and Asenputte, which later became the German Hasenpoth. The roots of the ancient name of Aizpute seem to be found in the Finno-Ugric languages from the words Ase and Ason, which mean an 'actively inhabited place'. Famous linguist Jānis Endzelīns believed that the origin of the place name is most likely Baltic, possibly derived from the Lithuanian word pùsti ('pamt, tūkt'), meaning 'place behind the hill'.

Various archaeological studies have shown that the area has been inhabited earlier than mentioned in written sources. During quarrying, an early Iron Age (2nd-4th century AD) settlement discovered during archaeological excavations in Misiņkalns was destroyed, as were nearby Curonian burial mounds (11th-13th century AD). There are at least 22 known burial mound sites in the Aizpute area. About 2 km south of Aizpute is Ormkalns, an ancient Couronian hillfort with a sacred spring at its foot, and to the south of it is a mound (Upurkalns), which is believed to have been an ancient Couronian place of worship.

In the 9th century, the Couronians built Beida Castle on the site of present-day Aizpute, from which the surrounding district was governed. It was located on the right bank of the Tebra River, near the Riga-Prussia trade and military road. The castle and its surroundings became a populated area during the heyday of the Couronian people, and it is believed that it was one of the most populated areas in the Bandava region. With the arrival of the Livonian Order in Aizpute, the old Latvian name of the castle, Beida, also disappeared.

In 1248, Dietrich von Grüningen Master of the Livonian Order, ordered the construction of Aizpute Castle on the left bank of the Tebra River, opposite Breida Castle, which is why 1248 is considered to be the founding year of the town of Aizpute. In 1253, after the division of Courland, Aizpute became part of the Bishopric of Courland. As early as 1254, a church was built on the site of Beida Castle. Part of the remains of the church walls from that time are now part of the stone church built in 1730, which was rebuilt in 1860. In 1258, the Couronians and the Lithuanians rebelled against the Livonian Order and in 1260, in the Battle of Durbe, they destroyed almost the entire army of the Order and killed the Master of the Order, von Hornhausen. The Curonians recaptured Aizpute, and the Bishop of Courland was only able to return there in 1295, when the Order had regained its strength.

After the Order eventually consolidated its power in the early 14th century, a settlement soon sprang up around the newly built castle, as the Order not only enjoyed a favorable defensive position here, but also, thanks to the convenient transport links along the Tebra River to the Baltic Sea, it was seen as having potential for development as a center of trade. On March 17, 1378, Otto, Bishop of Courland, granted Aizpute Magdeburg rights, marking the town's boundaries with plots of land, fields, and meadows. Thanks to its extensive trade, it soon became a notable town. Around 1484, a Franciscan convent was established in Aizpute, where the so-called Poor Clares lived. In 1523, the convent suffered greatly from a fire of unknown origin, which can most likely be explained by the recent start of the Reformation and the general hostile attitude towards Franciscans.

In 1559, King Frederick II of Denmark bought the rights to Saaremaa from the last Bishop of Courland, Johann Minhauzen, and soon after, through the mediation of Domprovost Ulrich Bär, also bought the rest of the Courland Bishopric territory, including Aizpute, paying 30,000 thalers for all the properties. He left the purchased properties to his younger brother, Duke Magnus of Holstein.

Although he was crowned King of Livonia by Ivan IV of Russia, Magnus' reign was full of adversity. Living beyond his means and income, he squandered all his property and possessions, except for the town of Piltene, thus losing the tsar's favor. Magnus finally surrendered to Polish rule and, fleeing the tsar's wrath, settled in Piltene, where he died in poverty on March 18, 1583, leaving no heirs. The Polish king, who ruled over the Piltene region, had already promised Duke Gothard Ketler of Courland in an agreement dated February 28, 1561, to merge the Bishopric of Courland with the duchy, but this did not happen.