• The first ever display of works of overlooked 17th century artist Cornelius Johnson, court painter to Charles I, has opened at the National Portrait Gallery off Trafalgar Square. Cornelius Johnson: Charles I’s Forgotten Painter features rarely viewed portraits of the king’s children including the future Charles II, James II and Mary (later Princess of Orange-Nassau) as well as a painting of Mary’s son William – all of which have been taken from the gallery’s collection. Overshadowed by Sir Anthony van Dyck, Johnson – who emigrated to The Netherlands when the English Civil War broke out – has been largely ignored by art historians despite the breadth of his work – from group portraits, such as his largest surviving English painting, The Capel Family, to tiny miniatures – and the fact that he is thought to be the first English-born artist who took to signing date his paintings as a matter of course, something he is believed to have picked up during his training in The Netherlands. The display features eight painted portraits and six prints from the gallery’s collection as well as three paintings from the Tate. Runs until 13th September in Room 6. Admission is free. For more, see www.npg.org.uk. PICTURE: King Charles II by Cornelius Johnson , 1639. © National Portrait Gallery, London.

• Trafalgar Square will be at the centre of London’s St George’s Day celebrations on Saturday with live music, celebrity chefs, a masterclass by leading tea experts and children’s games and activities. The musical lineup will feature the band from the West End musical Let It Be and the Crystal Palace Brass Band – one of the few traditional brass bands remaining in London. The free event runs between noon and 6pm on Saturday. For more, see www.london.gov.uk/stgeorges.

• Indigenous Australia, the first major exhibition in the UK to present a history of Indigenous Australia through objects, opens at the British Museum today. Drawing on the museum’s collection, Indigenous Australia features objects including a shield believed to have been collected in Botany Bay on Captain Cook’s voyage of 1770, a protest placard from the Aboriginal Tent Embassy established in 1972 and contemporary paintings and specially commissioned artworks from leading indigenous artists. Many of the objects have never been on display before. Runs until 2nd August. Admission charge applies. For more, see www.britishmuseum.org.

• Thirty prints from the Royal Collection will be on show at The London Original Print Fair to mark its 30th anniversary. The fair runs at the Royal Academy from today until Sunday and among the selected works from the more than 100,000 prints in the Royal Collection are the 2.3 metre long woodcut by Albrecht Durer entitled Triumphal Cart of the Emperor Maximillian (1523), Wenceslaus Hollar’s four etchings of tropical Seashells (c1650), a sequence of proofs of Samuel Reynolds’ portrait of King George III at the end of the monarch’s life, and lithographs produced by Queen Victoria and Prince Albert dating from 1842. For more on the fair, see www.londonprintfair.com. For more on the Royal Collection, see www.royalcollection.org.uk.

• The question of what is meant by the concept of luxury is under examination in the V&A’s new exhibition What is Luxury? Opening at the South Kensington museum Saturday, the exhibition will feature a range of luxury objects – from the George Daniels’ Space Travellers’ Watch to a Hermés Talaris saddle, and Nora Fok’s Bubble Bath necklace. Also on show in a section of the exhibit looking at what could determine future ideas of luxury is American artist Gabriel Barcia-Colombo’s DNA Vending Machine (complete with prepackaged DNA samples) and Henrik Nieratschker’s installation The Botham Legacy which tells the fictional story of a British billionaire who sends altered bacteria into space in an attempt to find valuable metals on distant plants. Runs until 27th September. Admission charge applies. See www.vam.ac.uk/whatisluxury.

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