Question: Who is the sibling of the artist who painted the Portrait of Baudouin de Lannoy?

full_context: Document 1: Self-Portrait with a Sunflower: Self-Portrait with a Sunflower is a self-portrait by Anthony van Dyck, a Flemish Baroque artist from Antwerp, Spanish Netherlands. The oil on canvas is thought to have been painted between the years 1632-1633. Produced at the height of his fame, Anthony van Dyck served as "principal Paynter in order to their Majesties" in the court of Charles I of England whilst working on this self-portrait. The symbolism behind the sunflower and gold chain have been a point of contention amongst various art historians. His successful ventures in the southern part of the Netherlands and Italy propelled him into a career as court painter and made him a favourite of King Charles I and his court. Van Dyck's devotion for capturing the likeness of his models gave him authority over the world of portraiture long after his death in 1641. With such a long and storied career in art, his portrait technique evolved into what is referred to as his Late English period as seen in "Self-Portrait with a Sunflower". This work is now in the private collection of the Duke of Westminster, housed at Eaton Hall in Cheshire.
Document 2: 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 3: 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 4: 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 5: 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 6: 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 7: Portrait of a Lady with a Squirrel and a Starling: Portrait of a Lady with a Squirrel and a Starling is an oil-on-oak portrait completed in around 1526–1528 by German Renaissance painter Hans Holbein the Younger. The painting shows a demurely dressed young woman sitting against a plain blue background and holding in her lap a squirrel on a chain eating a nut; a starling sits on a fig tree in the background with its beak pointing at her right ear. The subject of this portrait is believed to be Anne Lovell, wife of Sir Francis Lovell (d. 1551), an Esquire of the Body to Henry VIII.
Document 8: 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 9: Madonna of Chancellor Rolin: The Madonna of Chancellor Rolin is an oil painting by the Early Netherlandish master Jan van Eyck, dating from around 1435. It is kept in the Musée du Louvre, Paris, and was commissioned by Nicolas Rolin, aged 60, chancellor of the Duchy of Burgundy, whose votive portrait takes up the left side of the picture, for his parish church, "Notre-Dame-du-Chastel" in Autun, where it remained until the church burnt down in 1793. After a period in Autun Cathedral, it was moved to the Louvre in 1805.
Document 10: Wilton Diptych: The Wilton Diptych () is a small portable diptych of two hinged panels, painted on both sides, now in the National Gallery, London. It is an extremely rare survival of a late Medieval religious panel painting from England. The diptych was painted for King Richard II of England, who is depicted kneeling before the Virgin and Child in what is known as a donor portrait. He is presented to them by his patron saint, John the Baptist, and by the English royal saints Edward the Confessor and Edmund the Martyr. The painting is an outstanding example of the International Gothic style, and the nationality of the unknown artist is probably French or English.
Document 11: 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 12: 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 13: 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 14: 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 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: Who developed Portrait of Baudouin de Lannoy? Answer: Jan van Eyck
Jan van Eyck >> sibling Answer: Hubert Van Eyck