The 11th century Portolan chart estimated at €50,000-80,000 at Il Ponte in Milan.

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The previously unknown, decorated and illuminated chart on vellum measures 2ft 7in x 3ft 3in (80cm x 1m) and was pasted onto wood sometime in the 1970s. It is attributed to the circle of Vesconte Maggiolo, the most important 16th century cartographer from Genoa.

The nautical chart shows Europe, north Africa, the Atlantic Ocean with the Canary Islands and the northern lands of Iceland, Sweden and Norway.

The Red Sea is at the south-eastern border and the coastal cities on the Mediterranean are represented in great detail. The decoration includes eight compass roses and 28 vignettes of cities such as Venice and Genoa, each with its flag.

The estimate is €50,000-80,000.