Osias Beert or Osias Beert the Elder (c. 1580 – 1623/24) was a Flemish painter active in Antwerp who played an important role in the early development of flower and "breakfast"-type still lifes as independent genres in Northern European art. He has been recognized as one of the most influential artists of the earliest generation of still life painters in Flanders.
Little is known about this artist's early life. It is believed that he was born in Antwerp around 1580 and studied under the little-known Andries van Baesrode (or 'van Baseroo'). He joined the city's Guild of St. Luke in 1602 and married Marguerite Ykens on 8 January 1606.
Beert was not only a painter but also traded as a cork merchant. Beert was also a member of one of the local Chambers of rhetoric, which suggests he was involved in intellectual pursuits other than painting. He is believed to have died in Antwerp at the end of 1623 or 1624.
His pupils included Frans van der Borch, Frans Ykens (who was his nephew), Paulus Pontius and Jan Willemsen. Beert’s son, Osias Beert the Younger (1622–78), was also a painter but is unlikely to have studied under his father since his father is believed to have died when the son was very young.
Osias Beert is mainly known as a painter of flowers and banquet (breakfast) pieces, genres in which he played a pioneering role. He rarely signed or monogrammed and never dated his work. Of his works created on copper three bear the mark of the panel maker Pieter Stas and the dates 1607, 1608 and 1609. Even while a lack of dated works has made it difficult to date his work, stylistic analysis allows a tentative chronology. The works with a high viewpoint and little overlapping of objects are regarded as earlier than those with a lower viewpoint and a compacter arrangement of objects. These later works also have a better spatial coherence. 
Only four signed works by him are known and from these it has been possible to attribute four works in the Museum of Grenoble to him. Since knowledge about this early stage of the Flemish still life is still fragmentary there has been a tendency to attribute too many works to Beert. Some works attributed to him are likely by his pupils, while some attributed to Osias Beert the younger were probably painted by his father.
Osias Beert often painted on oak panels, using a glazing technique. By using multiple superimposed layers of very fluid oil he was able to obtain a transparency and a wide variety of colours. Some of his works are on copper.
He was one of the first artists to specialize in still life painting when the production of works in this genre was still minor and typically anonymous. His breakfast pieces, usually referred to by their Dutch name ontbijtjes ("little breakfasts"), represent the scene from a high viewpoint with a forced perspective.
This technique is commonly seen in early Flemish and Dutch still life painting. His compositions often show dense groupings in a balanced arrangement. His style is quasi-geometric and shows an eye for detail.
He strived for objectivity and displayed a strong sense of plasticity. His still lifes are bathed in an even and diffused light. An example is Still life with cherries and strawberries in China bowls (Gemäldegalerie, Berlin), which shows a banquet piece on a table that is slightly tilted so that the objects on it can be viewed without obstruction. The painting represents the last course of an eight to nine course banquet. The dragonfly and the butterfly have an emblematic meaning and represent the fight between good and evil.
He was known for his paintings of oysters and confectionery goods displayed orderly on tabletops together with precious wine glasses and Chinese porcelain. He was unmatched in his ability to depict oysters with light playing on the viscous and pearly flesh and the wetness distinguishing the oysters from the hard surface of the shell's interior. A good example is the Still life with oysters (National Gallery of Art, Washington), which shows oysters on a plate together with precious objects on a table extending on both sides outside of the canvas against a dark background.
His flower still lifes, often showing a vase of flowers in a shallow niche or a basket full of flowers, as is visible in Basket of Flowers at the Museum of Fine Arts, Houston are reminiscent of the works of Ambrosius Bosschaert. In his flower pieces each flower is displayed at the peak of its bloom and with great detail. The flowers depicted in the same bouquet often bloomed in different seasons and could never in reality have been displayed in the same vase. As such they symbolize the transitory nature of man's earthly existence. An example is the Bouquet in a niche in the Rockox House, Antwerp.
There is speculation that he collaborated with Peter Paul Rubens on at least one painting. He influenced his nephew Frans Ykens as well as other Antwerp artists, such as Jacob Foppens van Es and Jacob van Hulsdonck.
- Osias Beert I (Antwerp c. 1570-1624), Oysters on a pewter plate, sweetmeats and biscuits in a silver tazza, two façon-de-venise wine glasses and an orange in a niche at Christie's
- Mulders, Christine van. "Beert [Beet, Beirt, Bert], Osias [Osyas], I," Grove Art Online. Oxford University Press, accessed 15 April 2015.
- Osias Beert (I) at the Netherlands Institute for Art History (Dutch)
- Osias Beert I (Antwerp c. 1570-1624), A still life of dishes of fruit and drinking glasses arranged on a wooden tabletop at Johnny van Haeften
- Commentaires des chefs- d’oeuvre du musée de Grenoble du XVIe au XIXe siècle (French)
- Osias Beert I (? Antwerp c. 1580-1624), Peaches and raspberries on a wan-li kraak porcelain plate, with strawberries in a wan-li-krak porcelain beaker, with a glass of white wine on a tabletop at Christie's
- Norbert Schneider, Still Life, Taschen, 2003, p. 97-98
- Belkin, Kristin. "Beert, Osias." The Oxford Companion to Western Art. Ed. Hugh Brigstocke. Oxford Art Online. Oxford University Press. Web. 16 Apr. 2015
- Mark Doty, Still Life with Oysters and Lemon: On Objects and Intimacy, Beacon Press, 10 July 2002
- Osias Beert, Bouquet in a niche at barokinvlaanderen
- Vlieghe, Hans (1998). Flemish Art and Architecture, 1585-1700. Pelican history of art. New Haven: Yale University Press. ISBN 0-300-07038-1
- Media related to Osias Beert (I) at Wikimedia Commons