Pieter Cornelis "Piet" Mondriaan, after 1906 Mondrian (7 March 1872 – 1 February 1944), was a Dutch painter.

Mondrian was a contributor to the De Stijl art movement and group, which was founded by Theo van Doesburg. He evolved a non-representational form which he termed neoplasticism. This consisted of white ground, upon which he painted a grid of vertical and horizontal black lines and the three primary colors.

Mondrian`s arrival in Paris from the Netherlands in 1911 marked the beginning of a period of profound change. He encountered experiments in Cubism and with the intent of integrating himself within the Parisian avant-garde removed an `a` from the Dutch spelling of his name (Mondriaan).

Mondrian was born in Amersfoort in the Netherlands, the second of his parents` children. He was descended from Christian Dirkzoon Monderyan who lived in The Hague as early as 1670. The family moved to Winterswijk in the east of the country when his father, Pieter Cornelius Mondriaan, was appointed Head Teacher at a local primary school. Mondrian was introduced to art from a very early age. His father was a qualified drawing teacher, and, with his uncle, Fritz Mondriaan (a pupil of Willem Maris of the Hague School of artists), the younger Piet often painted and drew along the river Gein.

After a strictly Protestant upbringing, in 1892, Mondrian entered the Academy for Fine Art in Amsterdam. He already was qualified as a teacher. He began his career as a teacher in primary education, but he also practiced painting. Most of his work from this period is naturalistic or Impressionistic, consisting largely of landscapes. These pastoral images of his native country depict windmills, fields, and rivers, initially in the Dutch Impressionist manner of the Hague School and then in a variety of styles and techniques that attest to his search for a personal style. These paintings are most definitely representational, and they illustrate the influence that various artistic movements had on Mondrian, including pointillism and the vivid colors of Fauvism.

In 1911, Mondrian moved to Paris and changed his name (dropping an `a` from Mondriaan) to emphasize his departure from the Netherlands, and his integration within the Parisian avant-garde. While in Paris, the influence of the Cubist style of Picasso and Georges Braque appeared almost immediately in Mondrian`s work. Paintings such as The Sea (1912) and his various studies of trees from that year still contain a measure of representation, but, increasingly, they are dominated by geometric shapes and interlocking planes. While Mondrian was eager to absorb the Cubist influence into his work, it seems clear that he saw Cubism as a "port of call" on his artistic journey, rather than as a destination.

nlike the Cubists, Mondrian still attempted to reconcile his painting with his spiritual pursuits, and in 1913 he began to fuse his art and his theosophical studies into a theory that signaled his final break from representational painting. While Mondrian was visiting home in 1914, World War I began, forcing him to remain in The Netherlands for the duration of the conflict. During this period, he stayed at the Laren artist`s colony, where he met Bart van der Leck and Theo van Doesburg, who were both undergoing their own personal journeys toward abstraction. Van der Leck`s use of only primary colors in his art greatly influenced Mondrian. After a meeting with Van der Leck in 1916, Mondrian wrote, "My technique which was more or less Cubist, and therefore more or less pictorial, came under the influence of his precise method." With Van Doesburg, Mondrian founded De Stijl (The Style), a journal of the De Stijl Group, in which he first published essays defining his theory, which he called Neoplasticism.

When the war ended in 1918, Mondrian returned to France where he would remain until 1938. Immersed in the crucible of artistic innovation that was post-war Paris, he flourished in an atmosphere of intellectual freedom that enabled him to embrace an art of pure abstraction for the rest of his life. Mondrian began producing grid-based paintings in late 1919, and in 1920, the style for which he came to be renowned began to appear.

During late 1920 and 1921, Mondrian`s paintings arrive at what is to casual observers their definitive and mature form. Thick black lines now separate the forms, which are larger and fewer in number, and more of the forms are left white. This was not the culmination of his artistic evolution, however. Although the refinements became subtler, Mondrian`s work continued to evolve during his years in Paris.

In the 1921 paintings, many, though not all, of the black lines stop short at a seemingly arbitrary distance from the edge of the canvas although the divisions between the rectangular forms remain intact. Here, too, the rectangular forms remain mostly colored. As the years passed and Mondrian`s work evolved further, he began extending all of the lines to the edges of the canvas, and he began to use fewer and fewer colored forms, favoring white instead.

In 1934–35 three of Mondrian`s paintings were exhibited as part of the "Abstract and Concrete" exhibitions in the UK at Oxford, London, and Liverpool.

In September 1938, Mondrian left Paris in the face of advancing fascism and moved to London. After the Netherlands were invaded and Paris fell in 1940, he left London for Manhattan, where he would remain until his death. Some of Mondrian`s later works are difficult to place in terms of his artistic development because there were quite a few canvases that he began in Paris or London and only completed months or years later in Manhattan. The finished works from this later period are visually busy, with more lines than any of his work since the 1920s, placed in an overlapping arrangement that is almost cartographical in appearance. He spent many long hours painting on his own until his hands blistered, and he sometimes cried or made himself sick.

On 23 September 1940 Mondrian left Europe for New York aboard the Cunard White Star Lines ship RMS Samaria, departing from Liverpool. The new canvases that Mondrian began in Manhattan are even more startling, and indicate the beginning of a new idiom that was cut short by the artist`s death. New York City (1942) is a complex lattice of red, blue, and yellow lines, occasionally interlacing to create a greater sense of depth than his previous works. An unfinished 1941 version of this work uses strips of painted paper tape, which the artist could rearrange at will to experiment with different designs.

Piet Mondrian died of pneumonia on 1 February 1944 and was interred at the Cypress Hills Cemetery in Brooklyn, New York.