Of varying sizes – the largest measures 2ft 9in x 3ft 4in (86cm x 1.02m), the smallest (an obelisk) 2ft 10in x 5in (87 x 13cm) – they depict views of a harbour, various palaces and other architectural scenes and elements.
The panels are of Tuscan origin and are thought to have originally adorned the walls of a palace chamber.
They are attributed to Don Enrico Hugford, an artist of English origin, the son of a clockmaker, who became a monk – and later abbot – of the monastery of Vallombrosa near Florence.
The original version of scagliola was made by combining gesso with paint to create an illusion of pietra dura.
Hugford invented a new technique by combining ground crystalline selenite with paint to form a material that allowed a remarkable range of pastel colours that were not affected by the ravages of time.
The panels on offer once belonged to a family in Monschau near the German-Belgian border. After the war they were recovered from the ruins of the house and remained in their possession until 2002 when they were auctioned by Lempertz to a south German dealer.
This time around the guide is €600,000-700,000.