thumb|350px|Scaldis and Antverpia
Abraham Janssens I, Abraham Janssen I or Abraham Janssens van Nuyssen (1575–1632) was a Flemish painter, who is known principally for his large religious and mythological works, which show the influence of Caravaggio. He was the leading history painter in Flanders prior to the return of Rubens from Italy.
Life
Abraham Janssens was born in Antwerp as the son of Jan Janssens and Roelofken van Huysen or Nuyssen. There is some uncertainty regarding his year of birth. He was previously thought to have been born in the year 1567, but it is now more generally assumed that his date of birth was 1575.
thumb|left|300px|The Four Elements
Janssens studied under Jan Snellinck and was registered as a pupil in the local Guild of Saint Luke in 1585. He travelled to Italy where he resided mainly in Rome between 1597 and 1602. After returning to his home country he became a master in the Antwerp Guild in the guild year 1601–1602.
On 1 May 1602 he married Sara Goetkint (died in Antwerp on 7 April 1644) with whom he had 8 children, five of whom were still alive at the time of her death: Maria Anna, who also became a painter and married Jan Brueghel the Younger, Sara, Catharina, Lucretia and Abraham II.
In 1607 he became the dean of the Antwerp Guild of St Luke. This is also the time when he received his first major commissions, which initiated the most important period of his career.
thumb|230px|Allegory of Fickleness
Janssens joined in 1610 the Confrerie of Romanists, a society of Antwerp humanists and artists who had travelled to Rome. The diversity and high positions held by the Confrerie's membership offered him a good opportunity to meet with potential patrons.
Janssens died in Antwerp.
Janssens affixed the signature "Janssens van Nuyssen" to several of his pictures. It is believed that 'van Nuyssen' was the family name of his mother and that Janssens added it to his signature to distinguish himself from his namesakes as the family name Janssens was very common in 17th-century Flanders.
It is difficult to determine the chronology of Janssens's oeuvre, as he only dated or documented a few of his works.
thumb|230px|The Virgin and Child with the infant St John the Baptist
Early works
His earliest works are steeped in late 16th-century Mannerism and are characterized by an artificial design and a palette composed of dispersing colours. Still it remains possible that this impressive work had some influence on Rubens' painting as there are, for example, similarities in the colour of the garments of the female protagonists in Rubens' Samson and Delilah (c. 1609–10; National Gallery, London). The latter painting was likely commissioned as an altarpiece. This Caravaggesque composition predates comparable Dutch works such as Dirck van Baburen's Roman charity by a decade.