Question: What was Van Gogh's greatest ambition?
About the article "Vincent van Gogh", section "Portraits".

Candidate passages:
Van Gogh, known for his landscapes, seemed to find painting portraits his greatest ambition.
He said of portrait studies, "the only thing in painting that excites me to the depths of my soul, and which makes me feel the infinite more than anything else."
Van Gogh wrote further of the meaning he wished to evoke: "in a picture I want to say something comforting as music is comforting.
I want to paint men and women with that something of the eternal which the halo used to symbolize, and which we seek to communicate by the actual radiance and vibration of our coloring.
"As much as Van Gogh liked to paint portraits of people, there were few opportunities for him to pay or arrange for models for his work.
He found a bounty in the work of the Roulin family, for which he made several images of each person.
In exchange, Van Gogh gave the Roulin's one painting for each family member.
As the Roulin family was similar in size to Van Gogh's own, in his psychological approach Lubin suggested that Van Gogh may have adopted them as a substitute. 
Van Gogh's paintings of rose, or any flowers, are evocative of his quote, "Ah, what portraits could be made from nature with photography and painting."
Adrianus Jacobus Zuyderland was Vincent van Gogh's favorite model during his Hague period.
He appears in dozens of drawings, easily identified by his bald head and prominent white whiskers, and he was the model for the drawing which was the basis for van Gogh's later iconic painting "At Eternity's Gate". 
While in Saint-Remy interest began to build in van Gogh's work:   Theo, Van Gogh's brother, wrote in July 1889, that Camille and Lucien Pissarro, Père Tanguy, Erik Theodor Werenskiold and Octave Maus, secretary of the Les XX group in Brussels, had seen the paintings that he'd made in southern France.
On Van Gogh's behalf, Theo accepted an offer from Maus to exhibit Van Gogh's work at the Les XX group's upcoming exhibition.
Van Gogh's "Starry Night over the Rhone" and "The Irises" were exhibited at the Société des Artistes Indépendants on the third of September.
In January, 1890 six of Van Gogh's works were exhibited at the seventh exhibition of Les XX in Brussels along with, among others, Paul Cézanne, Camille Pissarro, Pierre-Auguste Renoir, Paul Signac and Henri de Toulouse-Lautrec.
Van Gogh's painting "The Red Vineyard" was sold to artist Anna Boch at the exhibition for 400 francs.
In the same month an article is published "Les Isole: Vincent van Gogh" in the "Mercure de France".
Ten of Van Gogh's works were presented at the March, 1890 Société des Artistes Indépendants.
Paul Gauguin, Claude Monet and Pissarro were quite impressed with his works.
Over this time, though, Van Gogh's health ebbed and flowed between periods of attacks, recovery and resumption of painting.
In April, 1890, near the end of van Gogh's stay at Saint-Paul's hospital, Theo wrote to his sister and mother, "I am so pleased that Vincent's work is being more appreciated.
If he were fit I believe that there would be nothing for me to desire, but it appears that this is not to be.
"The sale of "Red Vineyard" was the only sale of van Gogh's paintings made during his lifetime. 
Hirschig lodged with Vincent van Gogh at the Auberge Ravoux from around 17 June 1890 to shortly after Van Gogh's death.
He occupied the attic room next to Van Gogh's and these two rooms can still be seen at the inn.
It is not documented whether Hirschig was taking lessons from Van Gogh.
Anton Hirschig is mentioned in three of Van Gogh's letters.
At first Van Gogh thought Hirschig too "gentil" to be an artist and questions whether he would ever amount to anything.
However in what was to be Van Gogh's last letter (to his brother Theo), he softens his position and says that he thinks Hirschig has begun to understand things a little better.
Curiously that was also destined to be the last judgement he ever made on an artist in his letters.
Adeline Ravoux, the daughter of the innkeeper at the Auberge Ravoux, described Vincent's stay at the inn in a memoir.
She was some 12 years old at the time and approaching 80 when her memoir were published.
In the memoir, Adeline Ravoux recalls Hirschig as apparently more interested in beautiful girls than painting.
She recalls him as speaking French very badly and that consequently he and Van Gogh were obliged to speak Dutch together.
She didn't think Van Gogh took him very seriously.
She records Hirschig as leaving the inn shortly after Van Gogh's death.