800 years of Diemen (1226): Celebration!

In 2026, Diemen turns 800, and we will celebrate this from March 29 to September 30, 2026. We kick off the anniversary year with a party during the Great Diemen Birthday on March 29, 2026. In the months that follow, there is plenty to do and experience; large and small activities, from a walking tour to a festival, from the launch of a photo book to a sports tournament. Did you read Marcel van Roosmalen's column in the NRC (March 30)? In it, he discusses the party on Sunday, March 29, where the people of Diemen will celebrate with Lange Frans once again. But what do you know about Diemen, the city that is older than Amsterdam (which celebrated its 750th birthday in 2025)?

Diemen (general)

Diemen is a town and municipality in the province of North Holland. Within the municipal boundaries, in addition to the main town of Diemen and Oud-Diemen, lie the hamlets of Over-Diemen and Stammerdijk. The IJmeer lies to the north of the municipality. The municipality borders the municipality of Amsterdam to the north and south (IJburg to the north, Watergraafsmeer to the northwest, Amsterdam-Zuidoost and the Weesp urban area including the village of Driemond to the south, Muiden (part of the municipality of Gooise Meren) to the east, and the village of Duivendrecht (part of Ouder-Amstel) to the west). Diemen is part of the Amsterdam Metropolitan Area. The municipality has a total of 33.284 inhabitants (CBS, as of January 1, 2026).

Topographical municipal map of Diemen. Source: Wikipedia.

Flag of Diemen

The flag of Diemen, alongside the coat of arms of Diemen, is one of the official symbols of the Dutch municipality of Diemen. Since February 6, 2009, the flag has been identical to the municipality's coat of arms and can be described as follows: The flag consists of three stripes of equal height in the colors blue, white, and blue. In the white stripe are three swimming black ducks placed one behind the other.

Unlike the ducks on the coat of arms, these ducks are entirely black in color. The flag was designed because several municipalities in the area (Muiden and Weesp) flew a flag that closely resembled that of Diemen, and the municipality wanted to distinguish itself.

Coat of arms of Diemen

The coat of arms was officially granted on June 26, 1816, and with a crown on April 13, 1978. In the 18th-century Beelaerts van Blokland Manuscript, the coat of arms is mentioned as it was granted in 1816. The coat of arms also appears on, for example, the messenger's box of Amstelland from 1765.

The meaning of the coat of arms is unknown. The lordship was in the possession of Holland until 1731 and was then purchased by Amsterdam, which appointed Gerrit Corver as lord of the manor. The Corver coat of arms displayed 3 baskets and therefore bore no resemblance to the district coat of arms.

It is possible that the coat of arms represents the Diem (a former small river) or the Diemerdam, and the three birds the three parts of the Ambacht Diemen: Outersdorp, Buitenkerk, and Bovenkerk.

The stamp society De Zegelaars has issued a personalized stamp for 800 years of Diemen: The ducks are celebrating too.

Diemen (history and future)

Diemen derives its name from the small river Diem, which in the Middle Ages formed a connection between the Bijlmermeer, the Gaasp, and the Zuiderzee. About a thousand years ago, the peat meadow area was reclaimed and the first inhabitants settled. They probably originated from the vicinity of Utrecht. Excavations have shown that there was habitation near the Diem from the 11th century onwards. The oldest mention dates from 1033, making Diemen one of the first settlements in this area and about two centuries older than Amsterdam. In the 13th century, the Diem was dammed by the Diemerdam in the Diemerzeedijk. On March 29, 1226, Bishop Otto of Lippe granted Diemen as a fief to Lord Gijsbrecht II of Amstel.

In Oud-Diemen, the inhabitants lived on a mound approximately three meters high, near the current new housing development of Diemen-Noord, where a wooden church and houses stood. Remains of a stone church from the 15th century have been found during archaeological excavations. The foundations of the church at the 'Gedenkt te Sterven' cemetery have been made visible again. In the 17th century, Oud-Diemen was the center, and the inhabitants lived mainly from livestock farming. At that time, this small village was the subject of etchings and drawings by Rembrandt on several occasions. After the construction of the Muidertrekvaart and Weespertrekvaart in 1638 and 1640, the center of the municipality shifted to the Diemerbrug, near the current Hartveldseweg.

In the new settlement of Diemerbrug, churches, shops, businesses, schools, and homes were built in the 18th and 19th centuries. The blacksmith's shop on Ouddiemerlaan from 1749, the restored clandestine church De Hoop from 1787, and the former town hall on Hartveldseweg from 1882 are still tangible reminders of that time. The Roman Catholic church of Sint Petrusbanden on Hartveldseweg dates from 1910. Until 1896, the hamlet of Outersdorp also belonged to Diemen; it was situated on the site of the current Amsterdam Flevopark but was annexed by Amsterdam for the construction of the Indische Buurt, during which the hamlet disappeared.

From the mid-20th century onwards, Diemen began to grow rapidly as a commuter town for Amsterdam. The new residential areas built since then have transformed the character of the old agricultural village into that of a modern commuter town. The old villages merged, and subsequently Diemen-Noord and Diemen-Zuid emerged. Diemen has managed to maintain its position as an independent municipality, sandwiched between Amsterdam-Watergraafsmeer, Duivendrecht, and Amsterdam-Zuidoost.

800 years of Diemen

On March 29, 1226, the village of Diemen was leased to Knight Gijsbrecht van Amstel II by Bishop Otto of Utrecht. The deed in which this was recorded is the first written source in which the village of Diemen is mentioned. Diemen is probably even older. Excavations have uncovered remains of earlier habitation near the River Diem around the year 1000. But we view the official deed from 1226 as our birth certificate, and that is why we are celebrating our 800th anniversary in the year 2026. Time for a party!