The four-day auction by Sotheby's is stirring interest among serious collectors as well as die-hard Dutch fans of the popular House of Orange. Auctioneer Mark Grol said Monday's first day will give an indication of how far over the presale minimum estimate of about §1.5 million ($2.07 million) the auction would go.

He says interest is high, — not just from the Netherlands — but also from the US, Russia and China. A total of 1,725 lots gathered from the attics of seven royal palaces are being auctioned with the proceeds going to charity.