Thalassius of Libya was a 7th-century monk and abbot who lived in the Libyan desert. As a respected spiritual leader, he maintained a close relationship with Maximus the Confessor, who dedicated a book of scriptural explanations to him. Thalassius is primarily recognized for his theological writings, which addressed complex topics such as the incarnation of Christ and the sanctification of all creation. His insights into the Holy Spirit were likely derived from earlier patristic traditions, and his ideas later influenced the work of John Damascene.