Alfred Van Cleef (1872–1938) was the son of a stone-cutter and diamond broker. English Wikipedia describes him as a Dutch diamond-cutter; French Wikipedia says he was born in Paris. In 1895 he married his cousin Esther, known as Estelle, Arpels, the daughter of a precious-stone dealer, and the house of Van Cleef & Arpels grew out of his partnership with her family.
The founding date is given differently by the two main sources. English Wikipedia says Alfred and his father-in-law Salomon Arpels set up the business in 1896 and that, after Salomon's death, Alfred and two of his brothers-in-law, Charles and Julien Arpels, took premises at 22 place Vendôme, opposite the Ritz, in 1906. French Wikipedia dates the house itself to 1906, the year of the Vendôme boutique, with Charles joined by Julien and later Louis Arpels. Branches followed in the resorts of Dinard, Deauville, Vichy, Le Touquet, Nice and Monte-Carlo.
In 1925 the house won the grand prize at the Paris Exposition internationale des Arts décoratifs with a bracelet of ruby and diamond roses. In 1926 Alfred and Estelle's daughter, Renée Puissant, took over its artistic direction. The marriage of Alfred and Estelle is still presented by the house as the foundation of its theme of love. Alfred died in 1938.