The surname Tillo is likely of European origin, with its earliest traces found in the region that encompasses modern-day Belgium and Northern France. The origins of Tillo can be traced back to the medieval period, specifically around the 9th and 10th centuries. It is thought to derive from the Old Germanic name Thilo, a diminutive form of names beginning with "Diet-" (meaning people) or "Theud-" (meaning folk or tribe).

In linguistic terms, Tillo might also have connections to the Old Norse word "tíll," meaning "skillful" or "capable." This etymology suggests that the name could have originally been an occupational surname for someone who was particularly skilled, although this hypothesis remains speculative. Variations of the name, such as Tielo or Thillo, appear sporadically in medieval manuscripts and charters, indicating the fluidity in spelling common to the period.

Historical references to Tillo or its variants have been found in old manuscripts, including monastic records. One significant early record is a mention of Saint Thillo, also known as Theau or Tilloine, who was a Benedictine monk in the 7th century and is said to have hailed from Thuringia, Germany. He later lived in the Frankish Empire and was closely associated with the monastery of Solignac, in what is today the Limousin region of France. His life and deeds are documented in hagiographical texts, which provide one of the earliest recorded instances of the name.

Another early example is found in the Liber Vitae of Durham, a book listing benefactors of the Durham Cathedral priory. A mention appears of Tillo (or a name closely resembling it) as a minor noble associated with land grants in the 11th century. This presence suggests that the name likely had geographical and noble associations at various points in history.

As for individuals bearing the surname, not limited to religious figures, one notable person is Jan Tillo, a mayor of a Flemish town in the late 13th century. His name appears in several town charters and court records, pointing to his prominence in local governance during his time. Born around 1260, his influence extended until approximately 1320.

In the realm of academia, Margaret Tillo, an early 17th-century scholar, contributed to the budding Renaissance interest in classical texts. She was born in 1589 and her annotated manuscripts, particularly of Latin works, are preserved in several European university libraries. Her work provided valuable insights and is cited by later scholars.

The 18th century saw the emergence of Johann Tillo, a Prussian military officer, who played a significant role in several key battles during the Seven Years' War, particularly noted for his strategic insight and bravery. Born in 1725, he died in 1795, leaving a legacy documented in military histories of the period.

Another eminent figure, Maurice Tillo, an artist active in Paris during the early 19th century, made his mark on the Romantic movement. Born in 1783, his works often depicted dramatic landscapes and historical scenes. His contribution to art history is recognized through his membership in the French Academy of Fine Arts until his death in 1845.

Lastly, during the early 20th century, Anna Tillo, an activist and writer, emerged as a prominent voice for women's rights in Eastern Europe. She was born in 1871 and her writings, which include several influential essays and speeches, played a critical role in the early feminist movements. Her legacy continued beyond her death in 1932, inspiring future generations of advocates for equality.