Underneath the present town hall, archaeologists once traced the outline of a Roman villa. They called it Villa Crainham, and the name stuck. The villa endured until the 11th century, long after Rome itself had retreated, and by 1003 a church appears in charters beside it: crainham villa cum ecclesia. The Keulsebaan, the old Roman road from Brussels to Cologne, still cuts through Kraainem, and parts of its original surface remain underfoot. The lithic artifacts found here in 1928, dating to the Neolithic, suggest the site had drawn people for thousands of years before the Romans arrived. Three settlement cores eventually formed: High Kraainem around a Frankish court that became the Jourdain Castle, Low Kraainem where the Maalbeek met the Woluwe and water mills were turning by 1397, and Stokkel to the south, fed by the Woluwe abbey's slow work of making forest soil farmable.

When Belgium declared independence in 1830, the new nation needed newspapers, and Kraainem had paper mills. The mills had been there since the Middle Ages, but suddenly they mattered nationally. By 1892, the complex employed around a hundred craftsmen and included a grain mill and brewery. The town grew rich on it. Then the road network improved after the First World War, and by 1932 every mill had been closed and demolished. The industrial sites were reclaimed for housing after 1945, when paved roads finally connected the old high and low villages to Stokkel year-round. Kraainem's population climbed from 1,739 in 1920 to 3,330 by 1947, and the agricultural commune began turning into a suburb. Today only a small Industrial Heritage Monument marks what was lost. Kraainem remains, by some measures, one of the wealthiest municipalities in Belgium.

From the 1860s, Brussels' grand construction projects pushed the bourgeoisie out of the capital, and many settled around Stokkel. They brought French with them. A century later, the European institutions brought officials from across the continent, and NATO added more. The original Flemish-speaking population was steadily replaced. French is now the de facto lingua franca, English is widely understood, and Dutch survives in a shrinking minority. Officially, Kraainem is one of Belgium's faciliteitengemeenten, a Flemish commune with language facilities for French-speaking residents, a status that has fueled decades of constitutional argument. Older Flemish residents, watching housing prices climb, sometimes blame the newcomers for both. Wikivoyage's advice to visitors is direct: do not take a side in the language debate, because it can end in a brawl.

Look at Kraainem on a map and the shape is unmistakable. The commune narrows to just 160 meters at its waist, an hourglass scarred by highways pushing in from the west and north. The northern half lies flat in the Maalbeek valley around 40 meters above sea level; the south climbs to 120 meters in what was Sonian Forest until 1927. Roads went in, villas followed, and by 1967 the southern forest was almost entirely housing. A small fragment of the old beech canopy survives at the southernmost tip. From the air, Kraainem looks like a thin green wedge pressed between the Brussels ring road and the suburb of Wezembeek-Oppem, its three historic cores still legible if you know where to look, its newer southern half a quiet grid of villas where ambassadors and Eurocrats answer their front doors in three or four languages.

The Saint Pancras Church in High Kraainem dates to the 12th century, restored in 2012, and the faint trace of a double octagonal moat can still be read in the ground to its west, where a Frankish fortification stood until at least 1836. The Salesian monastery, designed by the religious architect Paul Bellot in 1928, sits along the Kapellelaan. The Peace Monument honors the commune's World War victims. Walk the Jozef van Hovestraat in Low Kraainem and you pass farmsteads dated 1727 and 1749, their white walls and red bricks unchanged. The whole loop, from the metro station through both old villages and back, takes between two and five hours depending on how long you linger. Most of the historic farmhouses are still private homes. Knock politely and many owners, the locals say, will happily walk you through the history themselves.