When St. Patrick returned to Ireland  in 433, "he passed a few days at the home of an Irish chieftain named Sechnan, in Meath. The whole family was converted, and the chieftain's young son, Benignus,  was so impressed with the Christian bishop that he sat by him while he slept, strewing flowers on him. . . . Benignus went with Patrick and became his dearest disciple and eventually his successor as bishop of Armagh. He was also a bard, sang with a lovely voice, and was nicknamed 'Patrick's psalmodist.'"
What did it mean to be a bard in fifth-century Ireland where "the systems of law, medicine, poetry, and music . . . were set to music, being poetical compositions"? The "bards, specially selected from amongst noble youths of conspicuous stature and beauty, 'had a distinctive dress of five colours, and wore a white mantle and a blue cap ornamented with a gold crescent.'"
"St. Patrick 'taught the sons of the bards how to chant the Psalms of David, and sing together the sweet music of the Church's hymns. . . . They might keep their harps and sing the songs of Erin's heroic youth, as in the days of old. But the great saint taught them how to tune their harps to loftier strains than those of the banquet hall or the battle-march.'"
St. Benen became one of the authors of the Senchus Mor (Grand Old Law). "Nine persons were appointed to arrange this book, namely, Patrick and Benen and Cairnech, three bishops; Laeghaire and Corc and Daire, three kings; Rossa mac Trechim, a Doctor of Bearla Feini, Dubhthach, a Doctor of Bearla Feini and a Poet, and Fergus the Poet."
"In the Senchus Mor were promulgated the four laws,  namely: (1) the law of fosterage; (2) the law relating to free tenants and the law relating to base tenants; (3) the law of social relationship; (4) the binding of all by their verbal contracts; for the world would be in a state of confusion if verbal contracts were not binding."
St. Benen also compiled the original Book of Rights,  in which we learn about the shoes, clothes, and ornaments worn by the bards and monarchs and chieftains of old Ireland and of the curved swords of battle, chessboards, mantles, steeds, ships, goblets, rings, bracelets, coats of mail, female slaves, etc., which "Every king is entitled to get from the king of Cashel." 
(In 1986, before the Jesuits sold Rathfarnham Castle,  they removed the famous Harry Clarke  stained glass windows and donated them to various hospitals and churches. Tullamore Parish got six of them, including St. Benen. In this country, we find a statue of St. Benen  in the Cathedral of Mary Our Queen in Baltimore.)