The name Gretta is believed to have originated from the Germanic root name Greta, which means "pearl." This name was popular in medieval times and has been used across various parts of Europe, particularly in Scandinavia and Germany.

The name Gretta is a variant spelling of the name Greta, which can be traced back to the Middle Ages. One of the earliest recorded instances of the name Greta appears in the 13th century Icelandic Saga of Erik the Red, where a character named Greta is mentioned.

In the 14th century, Saint Greta of Thunberg, a Swedish mystic and visionary, was a notable bearer of the name. She is known for her religious writings and her devotion to the Catholic faith.

During the Renaissance period, the Italian painter Greta da Fabriano, born around 1370, was a prominent figure in the art world. She is known for her frescoes and altarpieces, particularly in the Marche region of Italy.

In the 19th century, Greta Garbo, born Greta Lovisa Gustafsson in 1905, was a renowned Swedish-American film actress. She was a major star during the Golden Age of Hollywood and is often regarded as one of the greatest actresses of all time.

Another notable figure was Greta Thunberg, born in 2003, a Swedish environmental activist known for her passionate advocacy for climate change action. Her "Fridays for Future" movement inspired millions of people around the world to take action against climate change.

While the name Gretta is less common than its variant Greta, it has been used throughout history. For instance, Gretta Brooker Palmer, an American activist and advocate for women's rights, was born in 1889 and played a significant role in the suffrage movement.

Overall, the name Gretta has a rich history rooted in Germanic origins, with variations appearing across different cultures and time periods. It has been borne by notable individuals, from saints and artists to activists and actresses, reflecting its enduring appeal and cultural significance.