Mandarin Mansion is a gallery based in Haarlem, the Netherlands, ran by Peter Dekker. For over twenty years, he worked as a researcher and dealer in antique arms and armor. 

His foundation lies in the arms of China and its cultural orbit — the Himalayas, India, and Southeast Asia — with continued interest in the Islamic world and Japan. Particular personal interests include the Manchu military of the Qing dynasty, Sinhalese arms, early Japanese swords, South Indian arms, and the cross-cultural objects produced by Asian maritime trade.

Focused research into various niches within this field has established his reputation among discerning collectors, dealers, and institutions. His work has supported the Metropolitan Museum in New York, the Royal Armouries in Leeds, the British Museum, the Pitt Rivers Museum in Oxford, the Klingenmuseum in Solingen, the Rijksmuseum in Amsterdam, and many others. He also acts as an agent for collectors, sourcing specific, hard-to-find items or helping with authentication on potential purchases from third parties.