Emanuel was a unique historian. He was not merely a chronicler of the events of his time, but also a powerful and wealthy man who influenced those events.
In 1581 he was the Consul representing Dutch merchants in London. In that year he harbored Christiaen, the fourth secretary of William the Silent, Prince of Orange while he was being pursued by enraged Spaniards. He related the surrounding events in his work Album.
To help thwart the plots of the Spanish Ambassador at the Court of Queen Elizabeth, William the Silent enlisted one Willem Janszoon van Hoorn, the captain of the Sea Beggar, to pretend to accept a bribe from the Spanish Ambassador and enter into a conspiracy to surprise the English garrison at Flushing. To avoid trickery Don Bernadin de Mendoza had insisted on having the captain's small son as a hostage. Since trickery was indeed intended, the captain was desperate as to what might befall his son. The Prince of Orange promised him on his word of honour that he would have the boy kidnapped from the Spanish Embassy in London and safely conveyed home. Christiaen (later called "The Elder") was commissioned to redeem at all costs the Stadtholder's given pledge. Emanuel made some arrangements with the Secretary of State, Sir Francis Walsingham, who was in charge of security for the embassy. Nevertheless Christiaen and the boy narrowly escaped the pursuit of the enraged Spaniards who scoured the banks of the Thames for him and the boy. Emanuel was successfully in concealing them and effecting their escape.
In 1599 Emanuel van Meteren wrote a book titled Belgische ofte Nederlandsche Historie van onzen Tijden, detailing the events of the first part of the Eighty Years War between the Netherlands and Spain. Some of the accounts detail events that Emanuel actually witnessed. For instance he was with the Prince of Orange during the siege of Zaltbommel by the Spaniards.
In 1614 Emanuel was still serving as Consul in London. After Henry Hudson returned from his second voyage he related to Emanuel that there had been a mutiny in 1609, originating in quarrels between Dutch and English sailors. Emanuel had access to Hudson's journals, charts and logbooks, and recorded these events in Historie der Nederlanden.
In the same year he chronicled the adventures and demise of the French merchant François Le Fort.
In 1625 Emanuel published further material related to Hudson's third voyage.
Emanuel is also the author of Historia Belgica.