Elfrida Elizabeth Ionides, was the daughter of Dr George Bird. Her mother left her husband when the children were young and their aunt Lallah Bird came to look after them. She married stockbroker Lucas ('Luke') Alexander Ionides on 29 August 1869. They had seven children: Alexander George (b. 8 April 1870), Aglaia Mary (b. 27 November 1871), Cyril (b. 30 October 1873), Eirene (b. 19 April 1875), Philip (b. 24 October 1876), Dorothea (b. 1878), Basil (b. 28 June 1884). They separated in 1895.
Elfrida was well educated and attended Miss Buss's school, London, later entering the Oxford and Cambridge exam, although she did not attend university. Elfrida Ionides' husband was one of Whistler's earliest patrons. She often corresponded with Whistler and his mother on social arrangements. The Ionides family were all patrons of the arts, and 'open house' at 1 Holland Park continued after Elfrida's marriage, when she and Luke lived at 16 Holland Villas Road. They moved at the end of 1875 to a large house at 17 Upper Philimore Gardens, Campden Hill, London, as the family was growing. This required a substantial staff, and like other Ionides homes, was partly decorated by Morris.
However, in 1895, Ionides lost a great deal of money in a share scam; henceforth he lived alone in various lodgings. They separated irrevocably, Elfrida and the children initially going to live at Mapledurham. Elfrida had a very strong character and Luke avoided meeting her at events like family weddings for the rest of his life.
Ionides, Luke Memories, Paris, 1925, reprinted with an afterword by Julia Ionides, Ludlow, 1996; Ionides Junior, Alexander C., Ion: A Grandfather's Tale, Dublin, 1927; Butterworth, Dorothea, Ionides Family Tree, [privately published], 1936; Metaxas, K. H., 'The Ionides: a Greek family in Britain: family tree', The Greek Gazette, December 1995.