Boromir I was the son of Denethor I of Gondor and he became the eleventh Ruling Steward of Gondor in TA 2477. He was a valiant and noble captain, feared even by the Witch-king himself.

In TA 2475, during the last years of his father’s rule, Boromir fought the Uruk-hai attack on Gondor, defeating the enemy and regaining Ithilien. Osgiliath, however, had been completely ruined, its stone-bridge destroyed, and none dwelt there afterwards.

In that war Boromir received a Morgul-wound which shortened his days, so that his rule as Steward of Gondor lasted for only 12 years (TA 2477 - 2489). He was succeeded by Cirion.
Encyclopedia entry originally written by Nenyia