Until 1973 this painter was known as Aart van Antum, after his early signatures were interpreted as "Aert Antum". Later research showed his signature to be "AERT ANT(...)"; whereby the last letters are sometimes included in varying degrees of completion. One reason so little is known of him, is that his life and work were overlooked or omitted by early 17th and 18th century painter biographers such as Arnold Houbraken. Anthonisz was born at Antwerp. His parents moved the family in 1591 to Amsterdam. He was possibly a pupil of Hendrick Cornelisz Vroom. In 1603 he signed a paper in Amsterdam that he was 23 years old and had lived there for 12 years, when he married Baycken Coutermans from Mechelin. She in turn was given power of attorney by him to settle an inheritance in Mechelin in 1614. He was buried in the Zuiderkerk of Amsterdam.