Sotheby’s has announced that it will auction a group of unseen works of modern Indian art, including pieces by V. S. Gaitonde, Ram Kumar, Krishen Khanna, Mohan Samant and Piraji Sagaraon during its Modern & Contemporary South Asian Art sale. The works will go up for sale in London on September 29.

Several works from the collection of the Gunnar Hansen, an executive of engineering conglomerate Larsen & Toubro, will go up for sale. Together with his wife Inger, Hansen acquired seminal pieces of modern Indian art throughout the 1960 and 1970s, during a two-decade stay in India. One of the couple’s first purchases—and the leading lot in the sale—is an untitled red and orange abstract painting by Gaitonde estimated at £1.5 million–£2 million ($1.9 million–$2.6 million). Hansen bought the work directly from the artist in 1969.

Gaitonde has long been the leader of the Indian modern art market. The artist recently saw a new record at Mumbai-based auction house Pundole last week during a sale of works from the collection of Glenbarra Art Museum in Japan. The 1974 untitled painting sold for $5 million. In March, Sotheby’s sold a 1963 untitled painting by the artist for $1.8 million, beating its high estimate of $1.5 million.

Ishrat Kanga, Head of Sotheby’s London Modern and Contemporary South Asia Art Sale, called the Hansen collection a “perfect time-capsule” in a statement, adding that the work “demonstrates the depth and quality of abstract and non-objective art which was being created in India at this extraordinary moment.”

Other works in the sale come from prominent estates of Indian art patrons. Ruins (ca. late 1950s) by Ram Kumar is estimated at £80,000–£120,000 ($103,000–$155,000). The piece comes from the estate of scholar and collector Patwant Singh, who acquired the work directly from the artist in the 1960s. According to the house, the work was likely exhibited at the Tokyo Biennale in 1959. Alongside Gaitonde, Kumar is one of India’s most recognized artists. In 1950, he left his native city to study painting in Paris under Andre Lhote and Fernand Leger. His style shows influence of Amedeo Modigliani and European modernists.