Two tiny portraits by Rembrandt that had been lost to the world for 200 years and sold recently at auction for $14 million made their debut Wednesday at Amsterdam's Rijksmuseum.

The 20-centimetre high (eight-inch) oval portraits depict an elderly plumber named Jan Willemsz van der Pluym and his wife Jaapgen Carels.

The couple, painted in an unusually intimate style for Rembrandt, were friends of the artist's family and came from his hometown of Leiden in the Netherlands.

The paintings are the smallest known portraits by the 17th-century Dutch master, who was better known for much larger works commissioned by wealthy families.

The portraits were acquired by the Holterman family at a Christie's auction for more than £11 million in July and have been handed to the Rijksmuseum on long-term loan.

"The Rijksmuseum has the largest and most representative collection of Rembrandt paintings in the world," said owner Henry Holterman in a statement.

"I feel that these works belong in the museum," he said.

Experts from the Rijksmuseum used X-rays, infrared photography, and paint sample analysis to prove that the portraits were indeed painted by Rembrandt.

The portraits also exhibit a similar style to other works painted by Rembrandt at the time, "especially in the construction of the facial features and the loose brushwork", said the museum.