structural:scholar_edition
1880s

Strindberg and Siri's daughter Karin was born on 26 February 1880. Buoyant from the reception of The Red Room, Strindberg swiftly completed The Secret of the Guild, an historical drama set in Uppsala at the beginning of the 15th century about the conflict between two masons over the completion of the city cathedral, which opened at the Royal Theatre on 3 May 1880 (his first première in nine years); Siri played Margaretha. That spring he formed a friendship with the painter Carl Larsson. A collected edition of all of Strindberg's previous writings was published under the title Spring Harvest. From 1881, at the invitation of Edvard Brandes, Strindberg began to contribute articles to the Morgenbladet, a Copenhagen daily newspaper. In April he began work on The Swedish People, a four-part cultural history of Sweden written as a series of depictions of ordinary people's lives from the 9th century onwards, which he undertook mainly for financial reasons and which absorbed him for the next year; Larsson provided illustrations. At Strindberg's insistence, Siri resigned from the Royal Theatre in the spring, having become pregnant again. Their second daughter, Greta, was born on 9 June 1881, while they were staying on the island of Kymmendö. That month, a collection of essays from the past ten years, Studies in Cultural History, was published. Ludvig Josephson (the new artistic director of Stockholm's New Theatre) agreed to stage Master Olof, eventually opting for the prose version – the five-hour-long production opened on 30 December 1881 under the direction of August Lindberg to favourable reviews. While this production of Master Olof was his breakthrough in the theatre, Strindberg's five-act fairy-tale play Lucky Peter's Journey, which opened on 22 December 1883, brought him his first significant success, although he dismissed it as a potboiler. In March 1882 he wrote in a letter to Josephson: "My interest in the theatre, I must frankly state, has but one focus and one goal – my wife's career as an actress"; Josephson duly cast her in two roles the following season.

Having returned to Kymmendö during the summer of 1882, Strindberg wrote a collection of anti-establishment short stories, The New Kingdom. While there, to provide a lead role for his wife and as a reply to Henrik Ibsen 's A Doll's House (1879), he also wrote Sir Bengt's Wife, which opened on 25 November 1882 at the New Theatre. He moved to Grez-sur-Loing, just south of Paris, France, where Larsson was staying. He then moved to Paris, which they found noisy and polluted. Income earned from Lucky Peter's Journey enabled him to move to Switzerland in 1883. He resided in Ouchy, where he stayed for some years. On 3 April 1884, Siri gave birth to their son, Hans.

In 1884 Strindberg wrote a collection of short stories, Getting Married, that presented women in an egalitarian light and for which he was tried for and acquitted of blasphemy in Sweden. Two groups "led by influential members of the upper classes, supported by the right-wing press" probably instigated the prosecution; at the time, most people in Stockholm thought that Queen Sophia was behind it. By the end of that year Strindberg was in a despondent mood: "My view now is," he wrote, "everything is shit. No way out. The skein is too tangled to be unravelled. It can only be sheared. The building is too solid to be pulled down. It can only be blown up." In May 1885 he wrote: "I am on my way to becoming an atheist." In the wake of the publication of Getting Married, he began to correspond with Émile Zola. During the summer he completed a sequel volume of stories, though some were quite different in tone from those of the first. Another collection of stories, Utopias in Reality, was published in September 1885, though it was not well received.

In 1885, they moved back to Paris. In September 1887 he began to write a novel in French about his relationship with Siri von Essen called The Defence of a Fool. In 1887, they moved to Issigatsbühl, near Lindau by Lake Constance. His next play, Comrades (1886), was his first in a contemporary setting. After the trial he evaluated his religious beliefs, and concluded that he needed to leave Lutheranism, though he had been Lutheran since childhood; and after briefly being a deist, he became an atheist. He needed a credo and he used Jean-Jacques Rousseau nature worshiping, which he had studied while a student, as one. His works The People of Hemsö (1887) and Among French Peasants (1889) were influenced by his study of Rousseau. He then moved to Germany, where he fell in love with Chancellor Otto von Bismarck 's Prussia status of the officer corps. After that, he grew very critical of Rousseau and turned to Friedrich Nietzsche 's philosophies, which emphasized the male intellect. Nietzsche's influence can be seen in The Defence of a Fool (1893), Pariah (1889), Creditors (1889), and By the Open Sea (1890).

Another change in his life after the trial is that Strindberg decided he wanted a scientific life instead of a literary one, and began to write about non-literary subjects. When he was 37, he began The Son of a Servant, a four-part autobiography. The first part ends in 1867, the year he left home for Uppsala. Part two describes his youth up to 1872. Part three, or The Red Room, describes his years as a poet and journalist; it ends with his meeting Siri von Essen. Part four, which dealt with the years from 1877 to 1886, was banned by his publishers and was not published until after his death. The three missing years, 1875–1877, were the time when Strindberg was wooing von Essen and their marriage; entitled He and She, this portion of his autobiography was not printed until 1919, after his death. It contains the love letters between the two during that period.

In the later half of the 1880s Strindberg discovered Naturalism. After completing The Father in a matter of weeks, he sent a copy to Émile Zola for his approval, though Zola's reaction was lukewarm. The drama revolves around the conflict between the Captain, a father, husband, and scientist, and his wife, Laura, over the education of their only child, a fourteen-year-old daughter named Berta. Through unscrupulous means, Laura gets the Captain to doubt his fatherhood until he suffers a mental and physical collapse. While writing The Father, Strindberg himself was experiencing marital problems and doubted the paternity of his children. He also suspected that Ibsen had based Hjalmar Ekdal in The Wild Duck (1884) on Strindberg because he felt that Ibsen viewed him as a weak and pathetic husband; he reworked the situation of Ibsen's play into a warfare between the two sexes. From November 1887 to April 1889, Strindberg stayed in Copenhagen. While there he had several opportunities to meet with both Georg Brandes and his brother Edvard Brandes. Georg helped him put on The Father, which had its première on 14 November 1887 at the Casino Theatre in Copenhagen. It enjoyed a successful run for eleven days after which it toured the Danish provinces.

Before writing Creditors, Strindberg completed one of his most famous pieces, Miss Julie. He wrote the play with a Parisian stage in mind, in particular the Théâtre Libre, founded in 1887 by André Antoine. In the play he used Charles Darwin 's theory of survival of the fittest and dramatized a doomed sexual encounter that crosses the division of social classes. It is believed that this play was inspired by the marriage of Strindberg, the son of a servant, to an aristocratic woman.

In the essay On Psychic Murder (1887), he referred to the psychological theories of the Nancy School, which advocated the use of hypnosis. Strindberg developed a theory that sexual warfare was not motivated by carnal desire but by relentless human will. The winner was the one who had the strongest and most unscrupulous mind, someone who, like a hypnotist, could coerce a more impressionable psyche into submission. His view on psychological power struggles may be seen in works such as Creditors (1889), The Stronger (1889), and Pariah (1889).

In 1888, after a separation and reconciliation with Siri von Essen, he founded the Scandinavian Experimental Theatre in Copenhagen, where Siri became manager. He asked writers to send him scripts, which he received from Herman Bang, Gustav Wied and Nathalia Larsen. Less than a year later, with the theatre and reconciliation short lived, he moved back to Sweden while Siri moved back to her native Finland with the children. While there, he rode out the final phase of the divorce and later used this agonizing ordeal for the basis of The Bond and the Link (1893). Strindberg also became interested in short drama, called Quart d'heure. He was inspired by writers such as Gustave Guiche and Henri de Lavedan. His notable contribution was The Stronger (1889). As a result of the failure of the Scandinavian Experimental Theatre, Strindberg did not work as a playwright for three years. In 1889, he published an essay entitled "On Modern Drama and the Modern Theatre", in which he disassociated himself from naturalism, arguing that it was petty and unimaginative realism. His sympathy for Nietzsche's philosophy and atheism in general was also on the wane. He entered the period of his "Inferno crisis", in which he had psychological and religious upheavals that influenced his later works.

August Strindberg's Inferno is his personal account of sinking deeper into some kind of madness, typified by visions and paranoia. In Strindberg och alkoholen (1985), James Spens discusses Strindberg's drinking habits, including his liking for absinthe and its possible implications for Strindberg's mental health during the inferno period.