In 1844, Théodore's brother was made director. He too enjoyed an education in Antwerp and Paris, was a highly regarded historian and created images of many historic monuments in both Limburg and neighbouring Rhineland. All of which means he was welcomed with open arms. He was kept very busy setting up the Limburgs Geschied- en Oudheidkundig Genootschap (Limburg historical and archaeological society) and travelled frequently for historical research and to create his sketches and colour lithographs (the latter produced in Paris), which are still highly sought-after.
A visit by the education inspectorate in the mid-1850s unearthed a number of issues, including a very slapdash student administration system. This lead to his honourable dismissal.
Victor de Stuers was one of his students. In 1867, on his 24th birthday, he discovered and described, among other things, the 13th century fresco in the Dominican Church in Maastricht. After studying at Leiden University, he enjoyed a hugely successful career; at the same time, he gained nationwide renown for his pamphlet ‘Holland op zijn smalst’, (Holland at its narrowest point). Published in De Gids (The Guide), the pamphlet was a plea to protect historic monuments.
Along with Amsterdam professor Joseph Albertingk Tijm and architect Pierre Cuypers, he formed a powerful Roman Catholic triumvirate whose achievements included the building of the Rijksmuseum and the Central Station in Amsterdam. From the start of his career, De Stuers was involved in the restoration of medieval buildings in Maastricht and South Limburg.