In 1886, he attended the Seventh International Oriental Congress in Vienna, as well as the Colonial and Indian Exhibition in London, thus building an international network of acquaintances. In 1887, after disagreements with museum director Lindor Serrurier, Pleyte was hired as curator of the Ethnographisch Museum Artis, where the ethnological collection of the Society Natura Artis Magistra was managed. Besides a guide for the collection, Pleyte wrote during his Amsterdam period a large number of articles in scientific journals. Pleyte's promotion in 1896 to manager of the collection resulted in friction with the management of zoo. He subsequently became a Director of Brill; his father, an Egyptologist, served on the Board as well. In 1897, he developed an eight-volume catalog for the museum with an ethnographic collection of the South Seas. In the same year, he was asked to participate in the colonial exhibition at the Dutch pavilion of the 1900 World Exhibition in Paris. For this, he traveled to the Dutch East Indies, Sumatra, and Bali gathering artifacts, a trip which left a great impression upon him and inspired him to write a number of publications on Indonesian antiquities.