Short answers, pulled from the story.
Jorge Manrique was born around 1440 and died on the 24th of April 1479. He was killed during an attempt to take the castle of Garcimuñoz, which was defended by the Marquis of Villena, a staunch enemy of Isabel I of Castile.
Jorge Manrique's best known and best composition is the Coplas por la muerte de su padre, verses on the death of his father, which is still read today. Lope de Vega called it worthy to be printed in letters of gold.
Jorge Manrique's father was Rodrigo Manrique, who died on the 11th of November 1476 in Ocaña. The Coplas por la muerte de su padre is Jorge's funeral eulogy for him.
Jorge Manrique supported Queen Isabel I of Castile when her half-brother, Enrique IV, tried to make his daughter, Juana, crown princess, which triggered a civil war. Manrique actively fought on Isabel's side in that conflict.
The copla manriqueña, a stanza form used throughout the Coplas por la muerte de su padre, is named after Jorge Manrique. Each of the poem's forty stanzas has twelve lines of eight and four syllables, rhymed ABc ABc DEf DEf, with every third line a quebrado, or half line.
Jorge Manrique was born into a noble family of major literary standing. He was a great-nephew of Iñigo López de Mendoza, the marquis of Santillana, a descendant of Pero López de Ayala, chancellor of Castile, and a nephew of Gómez Manrique, corregidor of Toledo.