Pope canonises French couple Louis and Zelie Martin

Louis and Zelie Martin were the parents of Saint Theresa of Lisieux

Pope Francis has conducted the first canonisation of a married couple in a ceremony in St Peter's Square.

Louis and Marie-Zelie Guerin Martin, who lived in France in the 19th Century, were the parents of the much venerated Saint Therese of Lisieux.

The couple had nine children, four of whom died in infancy. The remaining five, all girls, became nuns.

The youngest, Therese, died of tuberculosis aged 24 in 1897 and was canonised in 1925.

Analysis by David Willey, BBC News, Rome

Known as "the little flower", Therese of Lisieux is widely venerated for the simplicity of her spiritual life.

Her autobiography, The Story of a Soul, has inspired generations of modern Catholics.

Her parents are being held up as a fine example of a Christian family while bishops from around the world are gathered here to discuss how best to minister to modern families - including divorced persons who remarry, who - under present Church rules - are barred from taking communion.

Pope Francis told the 50,000 people attending the ceremony that serving others - not seeking careers - should be the model for today's churchmen.

In his homily, Pope Francis said: "The holy spouses Louis Martin and Marie-Zelie Guerin practised Christian service in the family, creating day by day an environment of faith and love which nurtured the vocations of their daughters, among whom was Saint Therese of the Child Jesus."

The Pope also canonised an Italian priest and a Spanish nun, both of whom spent most of their lives helping the poor.