The king of Burgundy donated much of the land that today makes up Canton Jura to the Bishop of Basel in 999. The area was a sovereign state within the Holy Roman Empire for more than 800 years. After the Treaty of Westphalia in 1648 the Jura had close ties with the Swiss Confederation. In the Congress of Vienna the Jura was given to the Canton Bern. This act caused dissension. The Jura was French-speaking and Roman Catholic, whereas the canton of Bern was mostly German-speaking and Protestant. The people of the Jura region called for independence. After a long struggle, a constitution was accepted in 1977. In 1978 the split was made official when the Swiss people voted in favour of it, and in 1979 the Jura joined the Swiss Confederation as a full member. However, the southern part of the Jura region, which is also predominantly French-speaking but has a Protestant majority, opted not to join the newly formed canton, and instead remained part of Bern. This area is now known as Bernese Jura. The word Jura, therefore, may refer either to Canton Jura, or to the combined territory of Canton Jura and Bernese Jura.