The purpose of this study is to analyze the changes over time of the Ha-ha, which had considerable influence on the shape of the English style of landscape gardens, focusing particularly on the one at Stowe Garden, and from research into its role I would like to put forward some thoughts on the origins of the Ha-ha. Although Walpole credited Bridgeman for the creation of the Ha-ha, even before then they were used all over the country, originating in Levens Hall Garden. The Ha-ha that Bridgeman put in initially at Stowe garden was a stone wall or hedge but it was not an invisible barrier. However afterwards, when the then owner, Earl Temple, remodelled Stowe Garden in a 'Naturalistic' style, he took out the part of the wall which was above ground and linked the garden with the outer park using an optical 'trick'. This was the original role of the Ha-ha. It was not simply for continuity with the outer landscape but it was also to stop animals getting in whilst maintaining the view, and we can see the origins of the Ha-ha in the Moat surrounding the Medieval Garden and ditch and Deer Leap surrounding the Medieval Deer Park.