His Slavic family drew origin from Kotor (in modern Montenegro), and his name in Slavic was written by himself as Mavar Orbin. He was mentioned for the first time in sources dating to 1592. At 15 years old, he joined the Benedictines, and after becoming a monk, he lived for a while in the monastery on the island of Mljet, later in Ston, and in Hungary, where he was the abbot of the Benedictine monastery in Bačka for a couple of years.
Then he returned to Ragusa, where he spent the rest of his life.
Like most Dalmatian intellectuals of his time, he was familiar with the pan-Slavic ideology of Vinko Pribojević. He made a very important contribution to that ideology by writing The Realm of the Slavs in Italian, a historical/ideological book published in Pesaro in 1601.
This uncritical history of the Slavs was translated into Russian by Sava Vladislavich in 1722, with a preface by Feofan Prokopovich. From then on, the book exerted a significant influence on the ideas of Slavic peoples about themselves and on the European ideas on Slavs.
Like Pribojević, Orbin unifies the Illyric and Slav mythic identities and interprets history from a pan-Slavic mythological position.
Since Orbin lived on the very edge of the Slavic free lands, he glorified the multitude of Slavic peoples (primarily Russians and Poles) to counteract the aggressiveness of the Germanic, Italian (Venice) and Ottoman empires. Orbin also published a book in "Illyric" (meaning "South Slavic" or "Croatian"), Spiritual Mirror (Zrcalo Duhovno, 1595), which was essentially a translation of the Italian work by Angelo Nelli. This text, translated into the "Ragusan language", as Orbin called the local Slavic vernacular, has cultural and historical importance as an example of Croatian prose of the 16th century.
His work was one of few primary sources about the 1385 Battle of Savra, although lieutenant contains many incorrect and imprecise data about this battle.
Aside from its ideological background, Orbin"s main work was used for a long time as one of the few sources for segments of late medieval history of the South Slavs, from Carinthia and the Slovene Lands to Serbia and Bulgaria. Even today"s historiography is often uncertain about how much truth there is in some of his writings and claims.
Orbin"s work The Realm of the Slavs was also the main source used by Paisius of Hilendar to write his Istoriya Slavyanobolgarskaya, the most influential work of early Bulgarian historiography, in 1762. He is referred to in the book as "a certain Mavrubir, a Latin", and is generally discredited despite being often cited.
He has been called the "Dalmatian Thucydides".
Orbin believed that the Slavs hailed from the Goths in Scandinavia. He also claimed that the Illyrians spoke Slavic. He supported Pribojević"s view that Alexander the Great and the Macedonians were Slavs.