A report from 1844
In February 1844 the town clerk described his village in a report to the district commissioner. Diegem covered 532 hectares in the Woluwe valley, three quarters of a mile from Brussels. About eight in ten inhabitants (1,052 people) lived in the centre, the others on the Lo. The village was crossed by the Brussels-Haacht road and by a road linking it to the Brussels-Leuven road.
The farmers grew wheat, rye, barley, oats and potatoes; on the stony soil more rye than wheat. Besides farming, the people of Diegem lived from the quarries. There was a paper factory with about 60 workers and 8 mills were turning: 6 water mills and 2 windmills. There were two primary schools, one for boys and one for girls, but many boys went to work in the factory or on the land at an early age. The inhabitants were strictly Catholic and spoke only Flemish, although the clerk wrote his report in French.
The water was not pure everywhere, except that of the Sint-Cornelisborre spring. The previous winter there had been typhus, but no one died. On the higher-lying Lo, the clerk wrote, people fell ill less often and even lived longer than in the valley. In his view the only remarkable thing in the village was the church tower.
In the 1930s
Almost a century later, Eugeen De Seyn described Diegem as a municipality of 547 hectares between two plateaus, 8.5 km from Brussels, with rolling sandy, clay and chalky soil. He mentioned the quarries, farming, the chicory and paper factories and the flower and tree nurseries, the castle with its 15th-century gatehouse and the church with its Renaissance altars, its pulpit of 1687 and the tombstone of Karel van Brecht. Diegem was a busy place of pilgrimage to Saint Cornelius, and on the Lo stood a modern church from 1930.