Roger de Mowbray, 1st Baron Mowbray (1254—21 November 1297), was an English

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 peer

Peerage

The Peerage is a legal system of largely hereditary titles in the United Kingdom, which constitute the ranks of British nobility and is part of the British honours system...

 and soldier.

The son of another Roger de Mowbray, served in the Welsh and Gascon Wars. He was summoned to the Parliament of Simon de Montfort

Simon de Montfort, 6th Earl of Leicester

Simon de Montfort, 6th Earl of Leicester, 1st Earl of Chester , sometimes referred to as Simon V de Montfort to distinguish him from other Simon de Montforts, was an Anglo-Norman nobleman. He led the barons' rebellion against King Henry III of England during the Second Barons' War of 1263-4, and...

 in 1265, but such summons have later been declared void. However, in 1283 he was summoned to Parliament by the King as Lord Mowbray.

De Mowbray married Rose, a daughter of Richard de Clare, 6th Earl of Gloucester. They had at least two children:

• John
  John de Mowbray, 2nd Baron Mowbray
  John de Mowbray, 2nd Baron Mowbray was the son of Roger de Mowbray, 1st Baron Mowbray.De Mowbray served in the Scottish wars of Edward I...
  
  , who would succeed his father to the barony
• Alexander, who apparently took up residence in Scotland
  Scotland
  Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
  
  .