The plan to establish a museum gives Helene direction. While she initially purchased works of art for personal reasons, she now wants to create a collection ‘for the benefit and enjoyment of the community’. A collection that offers an overview ‘of the development of modern art from the positive Realism of around 1860 to the art of today, taking in Impressionism, Pointillism and Cubism’. In practice, she focuses mainly on French and Dutch art, with an extremely important position reserved for Vincent van Gogh. Under Bremmer’s guidance, contemporary artists are also brought to light.

Helene is not alone in taking Bremmer’s advice for her collection. Many similar collections develop around Bremmer. Recognizable by the presence of work by Charley Toorop, Bart van der Leck, and also older artists such as Jan Toorop, Floris Verster and Johan Thorn Prikker. There are often works from the Hague School, but also always Delft Blue and Chinese porcelain. Helene’s collection develops into the largest and most important Bremmerian collection. Bremmer is given plenty of leeway. Later, Helene would write about him: ‘He was my first minister and beside him I felt like a queen’.

Helene increasingly accompanies Bremmer on visits to galleries and auctions in the Netherlands and abroad. In 1912 she spends no less than 280,000 guilders on works of art, 115,000 guilders of which in the month of April alone. In that month in Paris, she acquires 15 paintings by Van Gogh and 2 harbour views by Georges Seurat and Paul Signac. Shortly thereafter, she purchases another 15 paintings at the auction of the Hoogendijk Collection in Amsterdam, including work by Jean-Baptiste Corot, Jan Toorop, Odilon Redon and Honoré Daumier and another 4 paintings by Van Gogh. Bridge at Arles (Pont de Langlois) immediately becomes a favourite piece; for Helene it is one of ‘the most beautiful, most powerful, the crystal-clearest’.

Helene is able to do all this thanks to the wealth that her husband accumulates with Müller & Co. Anton also regularly visits auctions and galleries with Bremmer. Although he initially displays a preference for 17^th century painting, he also develops an eye for modern art under Bremmer’s influence. He is also interested in Van Gogh, but for Anton speculative considerations and the desire to be ahead of others always play a role. It is partly due to him that Helene acquires so many works by her favourite artist.

Although Helene does not want her own preference and taste to play a role, she does leave her own idiosyncratic mark on the collection. She does not collect fauvists or German expressionists. Later movements such as Dada and Bauhaus are also too unfamiliar to her. She discovers futurism too late to be able to make important acquisitions. But under Bremmer’s leadership she sometimes outdoes herself. For instance, at an early stage she purchases cubist works such as Still life with oil lamp by Juan Gris and Tableau no.1 by Piet Mondriaan. To broaden the collection, she now also acquires a number of old masters, including Venus and Amor by Hans Baldung Grien.

In May 1912 Anton buys the building next to the headquarters of Müller & Co. At Lange Voorhout no.1 in July 1913, Helene shows her art collection for the first time, with work by Seurat, Signac, Théo van Rijsselberghe and a small room adorned with work by Redon on the ground floor. The largest room is for Van Gogh, which she regards as the heart of her collection. Slowly but surely, the ‘ultra-moderns’ are hung on the first floor: Juan Gris, Auguste Herbin, Van der Leck and Mondriaan. 'Museum Kröller' is free to visit, but visitors must request a ticket in writing in advance. The public mainly consists of the wealthy bourgeoisie, students of Bremmer, but also artists and art academy students.