Gioacchino Hierschel de Minerbi was born 18th March 1834 in Trieste, then the port of the Austrian Empire, the son of Leone Hierschel, a member of one of Trieste's leading Jewish families, and Clementina Minerbi. He had a sister, Ernesta, born in 1854, and also a Clara Zoe and possibly an Elodia; and a brother, Oscar, the diplomat. He trained as an artist, and spent his twenties and thirties painting in Holland, Dordrecht and Rotterdam and studying at the Academy in The Hague. It was whilst living here that he adopted the name Joachim Van Hier, signing all his works 'Van Hier'. He seems to have spent the latter years of his life in London, producing large numbers of picture postcards for Raphael Tuck and Sons painting under the name of Professor Van Hier, and working in the style of the Impressionists, helping to popularise their style to a wider audience. He specialised in sunsets, river scenes, often the Thames, views of Venice, dramatic stormy sea scenes and rural landscapes, with distinctive impasto techniques in his skies, and a typical use of yellow, and an individualistic representation of the human figure foreshadowing Lowry. He was living in St James, London, according to the 1881 census, and married Lydia Selina Curtis in September 1893 in Brighton. She was born in Brighton in 1873, and in 1891 was a domestic servant with the Pitt family. She would have been aged 20 when she married him, when he was aged 59. He died in London on 23rd February 1905.
Addendum: I recently discovered that he married a second time at the end of his life. I shall try to add the details when I am in better health.