Hanuman Chalisa

The Hanuman Chalisa is a Hindu devotional hymn (stotra) addressed to Lord Hanuman. ... Chaupais eleven to twenty describe the acts of Hanuman in his service to Ram, with the eleventh to fifteenth Chaupais describing the role of Hanuman.

The authorship of the Hanuman Chalisa is attributed to Tulsidas, a poet-saint who lived in the 16th century CE. He mentions his name in the last verse of the hymn. It is said in the 39th verse of the Hanuman Chalisa that whoever chants it with full devotion to Hanuman, will have Hanuman's grace. Among Hindus worldwide, it is a very popular belief that chanting the Chalisa invokes Hanuman's divine intervention in grave problems