Luxembourgish art can be traced back to Roman times, especially as depicted in statues found across the country and in the huge mosaic from Vichten. Over the centuries, Luxembourg's churches and castles have housed a number of cultural artefacts but these are nearly all ascribed to foreign artists. The first examples of art with a national flavour are paintings and maps of the City of Luxembourg and its fortifications from the end of the 16th until the beginning of the 19th century, although these too were mostly created by foreign artists. Real interest in art among the country's own citizens began in the 19th century with paintings of Luxembourg and the surroundings after the country became a grand duchy in 1815. This was followed by interest in Impressionism and Expressionism in the early 20th century, the richest period in Luxembourg painting, while Abstraction became the focus of art after the Second World War. Today there are a number of successful contemporary artists, some of whom have gained wide international recognition.