This triangular region on the north bank of the Loire river lies between Saumur and Tours. The vineyards of Bourgueil and St. Nicolas de Bourgueil are planted mostly to Cabernet Franc, with a small amount of Cabernet Sauvignon. Vines have been cultivated here since Roman times, but the founding of the Abbey of Bourgueil, in 990, marked the beginning of the development of viticulture and winemaking. The vineyards are planted on two kinds of soil: lighter, warmer soils with high percentages of sand and gravel yield supple, fruity wines that can be drunk young; and vineyards on the south-facing hillsides where the soil contains more clay and limestone yield richer, earthier wines that take longer to reach their full potential. Most of the wines are red, although there is some rosé as well. The vineyards benefit from being open over the Loire river, which carries the Atlantic's regulating influence inland. The slopes are south facing, with forests to protect vines from harsh north winds. All of which creates a gentle, moderate climate for producing some of the best Cabernet Franc wines.