Scotland a territorial parish structure, with every community in Scotland having a local congregation. Scotland also has a significant Roman Catholic population, 19% professing that faith, particularly in Greater Glasgow and the north-west. After the Reformation, Roman Catholicism in Scotland continued in the Highlands and some western islands like Uist and Barra, and it was strengthened during the 19th century by immigration from Ireland. Other Christian denominations in Scotland include the Free Church of Scotland, and various other Presbyterian offshoots. Scotland's third largest church is the Scottish Episcopal Church. Islam is the largest non-Christian religion (estimated at around 75,000, which is
Scotland in the High Middle Ages doussane", meaning the dozen. The population of Scotland in this period is unknown. The first reliable information in 1755 shows the inhabitants of Scotland as 1,265,380. Best estimates put the Scottish population for earlier periods in the High Middle Ages between 500,000 and 1,000,000 people, growing from a low point to a high point. Linguistically, the majority of people within Scotland throughout this period spoke the Gaelic language, then simply called "Scottish", or in Latin, "lingua Scotica". Other languages spoken throughout this period were Old Norse and English, with the Cumbric language disappearing somewhere between 900 and 1100. Pictish may