The name Gustavo has its origins in the Old Swedish language, derived from the Germanic word "Gūstaz," which means "guest" or "stranger." This name gained popularity during the Viking Age, spanning from the late 8th to the late 11th century, when Swedish and Norse cultures had a significant influence across Europe and beyond.

The name Gustavo was initially used in Scandinavian regions, particularly in Sweden and Norway, before spreading to other parts of Europe through trade and exploration. It is believed to have been introduced to the Iberian Peninsula during the Reconquista period, when Christian kingdoms in the region sought to reclaim territories from the Moors.

One of the earliest recorded instances of the name Gustavo can be found in the Icelandic Sagas, a collection of narratives that document the lives and adventures of prominent Scandinavian figures from the 9th to the 11th centuries. The Saga of Gunnlaug Serpent-Tongue, written in the 13th century, mentions a character named Gustavr, which is considered a precursor to the modern form of the name.

Throughout history, several notable individuals have borne the name Gustavo. One of the earliest was Gustavo I Vasa (1496-1560), a Swedish king who played a crucial role in the establishment of the modern Swedish nation-state and the introduction of Protestantism in Sweden.

Another prominent figure was Gustavo Adolfo (1594-1632), also known as Gustavus Adolphus, a Swedish king and military leader who was instrumental in the Thirty Years' War, a conflict that shaped the religious and political landscape of Europe in the 17th century.

In the realm of arts and literature, Gustavo Adolfo Bécquer (1836-1870) was a Spanish Romantic poet and writer, renowned for his lyrical poetry and short stories, which captured the essence of the Romantic movement in Spain.

The name Gustavo has also been associated with scientific and philosophical figures, such as Gustavo Le Bon (1841-1931), a French social psychologist and sociologist who is considered a pioneer in the study of crowd psychology and mass behavior.

In more recent times, Gustavo Dudamel (born 1981) is a renowned Venezuelan conductor and violinist, who has achieved international acclaim for his musical leadership and commitment to promoting classical music education among underprivileged communities.