"Kathina" in Pali refers to the wooden frame which monks in ancient India used to sew their clothes on. The clothes thus prepared came to be known as Kathina clothes. On the Kathina frame the cloth could be stretched for cutting or sewing. Such a device was an aid to unskilled monks who made their robes from cast-off scraps of cloth which they cut with a knife.
The robes of today are made of new cloth but still consist of fourteen "patches" sewn together. The Buddha allows Kathina robes to be presented to the monks who have completed the three-month period of rains retreat.
The event in which the robes are offered to the monks is, therefore, known as the Kathina Ceremony or more commonly, the Robe-Presentation Ceremony.
Kathina is a main festival that is celebrated during October or November by Theravada Buddhists (i.e. the southern schools, mainly Sri Lanka, Thailand, Myanmar, Cambodia and Laos).
A worthy monk is chosen to receive a new robe, and then other monks are assigned to make it. During this time, it is said that acts of generosity will bring great merit to those who perform them.
Five monks who have spent Vassa correctly must be present at the festival. Vassa is the period of September and October when heavy rain stops the monks from wandering from place to place and causes them to settle down in a temple to apply themselves more strictly than usual to their religious way of life.