The name Johnna is a feminine variant of the name John, which has its roots in the Hebrew name Yohanan, meaning "Yahweh is gracious." The name was popularized by the biblical figure John the Baptist and later by the apostle John. The name has been in use since ancient times, with various spellings and forms across different cultures and languages.

In the early Christian era, the name John gained widespread popularity and was commonly used among the faithful. It was particularly popular in regions where Christianity flourished, such as Europe and the Middle East. The name Johnna emerged as a feminine form of John in several European languages, including English, German, and Scandinavian languages.

The earliest recorded use of the name Johnna dates back to the 12th century in England, where it was spelled as "Johanna." This spelling was influenced by the Latin and Greek forms of the name, "Iohannes" and "Ioannes," respectively. Over time, the name evolved into various spellings, including Johanna, Joanna, and eventually Johnna.

Throughout history, several notable individuals have borne the name Johnna. One of the earliest recorded figures was Johnna of Constantinople (c. 460-527), a Byzantine empress and the wife of Emperor Anastasius I. Another notable figure was Johnna of Montfort (c. 1292-1349), a French noblewoman who played a significant role in the Hundred Years' War.

In the 16th century, Johnna of Castile (1479-1555), also known as Juana la Loca, was the Queen of Castile and Aragon. She is renowned for her turbulent reign and alleged mental instability. Another famous Johnna was the Swedish playwright and novelist Johnna Spyri (1827-1901), best known for her children's book "Heidi."

During the 20th century, Johnna Woodruff (1923-2019) was an American tennis player and one of the leading African American athletes of her time. She won multiple Grand Slam titles and was inducted into the International Tennis Hall of Fame in 1985.

While the name Johnna has maintained a presence throughout history, its popularity has ebbed and flowed over time. It remains a poetic and elegant option for parents seeking a feminine name with deep historical roots and a connection to the biblical figure John.