Henriad is a common title used by scholars for Shakespeare's

William Shakespeare

William Shakespeare was an English poet and playwright, widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's national poet and the "Bard of Avon"...

 second historical tetralogy

Tetralogy

A tetralogy is a compound work that is made up of four distinct works, just as a trilogy is made up of three works....

, comprising Richard II

Richard II (play)

King Richard the Second is a history play by William Shakespeare believed to be written in approximately 1595. It is based on the life of King Richard II of England and is the first part of a tetralogy, referred to by some scholars as the Henriad, followed by three plays concerning Richard's...

; Henry IV, Part 1

Henry IV, Part 1

Henry IV, Part 1 is a history play by William Shakespeare, believed to have been written no later than 1597. It is the second play in Shakespeare's tetralogy dealing with the successive reigns of Richard II, Henry IV , and Henry V...

; Henry IV, Part 2

Henry IV, Part 2

Henry IV, Part 2 is a history play by William Shakespeare, believed written between 1596 and 1599. It is the third part of a tetralogy, preceded by Richard II and Henry IV, Part 1 and succeeded by Henry V.-Sources:...

; and Henry V

Henry V (play)

Henry V is a history play by William Shakespeare, believed to be written in approximately 1599. Its full titles are The Cronicle History of Henry the Fifth and The Life of Henry the Fifth...

.

While it is not known whether Shakespeare conceived of the plays as a cycle, these plays are often interpreted and performed in relation to each other, since they represent a continuous period of English history using recurring characters and including direct references to previous plays. The validity of the term "Henriad", however, is up for debate.

Some scholars include in the Henriad Shakespeare's First Tetralogy, comprising the plays Henry VI, Part 1

Henry VI, part 1

Henry VI, Part 1 or The First Part of Henry the Sixt is a history play by William Shakespeare, and possibly Thomas Nashe, believed to have been written in 1591, and set during the lifetime of King Henry VI of England...

; Henry VI, Part 2

Henry VI, part 2

Henry VI, Part 2 or The Second Part of Henry the Sixt is a history play by William Shakespeare believed to have been written in 1591, and set during the lifetime of King Henry VI of England...

; Henry VI, Part 3

Henry VI, part 3

Henry VI, Part 3 or The Third Part of Henry the Sixt is a history play by William Shakespeare believed to have been written in 1591, and set during the lifetime of King Henry VI of England...

; and Richard III

Richard III (play)

Richard III is a history play by William Shakespeare, believed to have been written in approximately 1591. It depicts the Machiavellian rise to power and subsequent short reign of Richard III of England. The play is grouped among the histories in the First Folio and is most often classified...

.