From the Roman name Iulianus, which was derived from Julius. This was the name of the last pagan Roman emperor, Julian the Apostate (4th century). It was also borne by several early saints, including the legendary Saint Julian the Hospitaller. This name has been used in England since the Middle Ages, at which time it was also a feminine name (from Juliana, eventually becoming Gillian).
Derived from the Slavic elements bolye “more, greater” and slava “glory”. This was the name of kings of Poland, starting in the 11th century with the first Polish king Bolesław the Brave.
From an Old Testament place name meaning “jawbone” in Hebrew, so called because it was the site where the hero Samson defeated 1,000 warriors using only the jawbone of a donkey as a weapon. It is also used in the Book of Mormon as the name of a prophet.