Question: Who is the sibling of the creator of The Portrait of a Man with a Blue Chaperon?

full_context: Document 1: Virgin and Child with Canon van der Paele: The Virgin and Child with Canon van der Paele is a large oil-on-oak panel painting completed around 1434–36 by the Early Netherlandish painter Jan van Eyck. It shows the painting's donor, Joris van der Paele, within an apparition of saints. The Virgin Mary is enthroned at the centre of the semicircular space, which most likely represents a church interior, with the Christ Child on her lap. St. Donatian stands to her right, Saint George — the donor's name saint — to her left. The panel was commissioned by van der Paele as an altarpiece. He was then a wealthy clergyman from Bruges, but elderly and gravely ill, and intended the work as his memorial.
Document 2: Portrait of Baudouin de Lannoy: Portrait of Baudouin de Lannoy is a small oil-on panel portrait by the Early Netherlandish painter Jan van Eyck, completed c. 1435. It shows Baldwin of Lannoy, a contemporary Flemish statesman and ambassador for Philip the Good at the court of Henry V of England. From surviving documents it is known that the work was commissioned to mark his entry into the order "Baudouin de Lanno". He is in a formal pose, holding a wooden stick in his right hand, and a gold ring on his little finger. Van Eyck's surviving early portraits typically show the sitter holding an emblem of his profession and class.
Document 3: Crucifixion and Last Judgement diptych: The Crucifixion and Last Judgement diptych (or Diptych with Calvary and Last Judgement) consists of two small painted panels attributed to the Early Netherlandish artist Jan van Eyck, with areas finished by unidentified followers or members of his workshop. This diptych is one of the early Northern Renaissance oil on panel masterpieces, renowned for its unusually complex and highly detailed iconography, and for the technical skill evident in its completion. It was executed in a miniature format; the panels are just high by wide. The diptych was probably commissioned for private devotion.
Document 4: Portrait of a Man with a Blue Chaperon: Portrait of a Man with a Blue Chaperon (or Portrait of a Man with a Blue Hood, earlier Portrait of a Jeweler or Man with a Ring) is a very small (22.5 cm x 16.6 cm with frame) oil on panel portrait of an unidentified man attributed to the Early Netherlandish painter Jan van Eyck.
Document 5: St. Anthony Beaten by Devils: This tryptch is missing a panel, lost when it was disassembled in 1777, but the panel with "St. Anthony Beaten by Devils" is currently on display at the Pinacoteca Nazionale. The painting depicts St. Anthony being clubbed by three devils who have surrounded him. According to stories, St. Anthony led a monastic life, and was tempted and tortured by devils as a test of faith.
Document 6: Self-portrait by Judith Leyster: Self-portrait by Judith Leyster is an Dutch Golden Age painting in oils in the collection of the National Gallery of Art that was offered in 1633 as a masterpiece to the Haarlem Guild of St. Luke. It was attributed for centuries to Frans Hals and was only properly attributed to Judith Leyster upon acquisition by the museum in 1949. The style is indeed comparable to that of Hals, Haarlem's most famous portraitist.
Document 7: Gothic altarpiece of Santes Creus: The Gothic altarpiece of Santes Creus is an altarpiece painted by Guerau Gener and Lluís Borrassà between 1407 and 1411. It is one of the key works of the International Gothic altarpieces in Catalonia, created for the Santes Creus Monastery. The MNAC museum retains the "Nativity", crowned by the figure of "St. John the Evangelist", and the Resurrection of Christ, while the rest of the tables are kept in one of the chapels of the cathedral of Tarragona. The altarpiece was commissioned to Pere Serra but apparently died without starting it. Guerau Gener, a connoisseur of València international Gothic, replaced him, but his untimely death made Lluís Borrassà, one of the major figures in the painting of the first international Catalan Gothic, to complete the project.
Document 8: The Judgement of Cambyses: The Judgement of Cambyses is an oil on wood diptych by Dutch artist Gerard David, depicting the arrest and flaying of the corrupt Persian judge Sisamnes on the order of Cambyses, based on Herodotus' "Histories". The diptych was commissioned in 1487/1488 by the municipal authorities of Bruges which requested a series of panels for the deputy burgomaster's room in the town hall.
Document 9: Young Man in a Fur Cap: A Young Man in a Fur Cap and a Cuirass (probably a Self Portrait) is a 1654 portrait painting by Carel Fabritius. It is an oil painting on canvas of 70.5 by 61.5 cm (27.8 by 24.2 in). The painting is generally considered to be a self-portrait. The work has been in the collection of the National Gallery in London since 1924.
Document 10: Portrait of Cardinal Niccolò Albergati: The Portrait of Cardinal Niccolò Albergati is a painting by early Netherlandish painter Jan van Eyck, dating to around 1431 and now in the Kunsthistorisches Museum of Vienna, Austria.
Document 11: Portrait of a Commander: Portrait of a Commander or A Commander Being Dressed for Battle is a portrait of an unknown man in plate armour, normally attributed to Peter Paul Rubens. In July 2010 it was sold for £9 million by Christie's after Sotheby's turned it down, suspecting its authenticity as a Rubens. In December 2011, the portrait was placed on loan with the Metropolitan Museum of Art in New York.
Document 12: Portrait of Margaret van Eyck: Portrait of Margaret van Eyck (or Margaret, the Artist's Wife) is a 1439 oil on wood painting by the Early Netherlandish master Jan van Eyck. It is one of the two latest of his surviving paintings, and one of the earliest European artworks to depict a painter's spouse. Completed when she was around 34, it was hung until the early 18th century in the Bruges chapel of the Guild of painters. The work is thought to be a pendant or diptych panel for either a now lost self-portrait known from records until 1769, or of Jan van Eyck's likely self-portrait now in the National Gallery in London.
Document 13: Portrait of an African Man: The Portrait of an African Man () also known as Portrait of a Moor () is a painting by the Netherlandish Renaissance painter Jan Mostaert. Mostaert probably made the painting between c. 1525 and 1530, or slightly earlier. The exact subject of the painting has long been unclear, although numerous ideas have been put forward, including that the depicted figure is a soldier, a nobleman or Saint Maurice. The portrait is significant in that it may portray the earliest portrait of a specific black man in European painting, though Saint Maurice, and Balthazar of the Three Kings or Biblical Magi, had long been usually portrayed as black.
Document 14: Annunciation (van Eyck, Washington): The Annunciation is an oil painting by the Early Netherlandish master Jan van Eyck, from around 1434–1436. The panel is housed in the National Gallery of Art, in Washington D.C. It was originally on panel but has been transferred to canvas. It is thought that it was the left (inner) wing of a triptych; there has been no sighting of the other wings since before 1817. The annunciation is a highly complex work, whose iconography is still debated by art historians.
Document 15: The Just Judges: The Just Judges or The Righteous Judges is the lower left panel of the "Ghent Altarpiece", painted by Jan van Eyck or his brother Hubert Van Eyck between 1430–32. It is believed that the panel shows portraits of several contemporary figures such as Philip the Good, and possibly the artists Hubert and Jan van Eyck themselves. The panel was stolen in 1934 and has never been found.
ground_truth: Hubert Van Eyck
sub_queries: The Portrait of a Man with a Blue Chaperon was made by whom? Answer: Jan van Eyck
Jan van Eyck >> sibling Answer: Hubert Van Eyck