You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Ottoman_Empire

Context:
Until the second half of the 15th century the empire had a Christian majority, under the rule of a Muslim minority. In the late 19th century, the non-Muslim population of the empire began to fall considerably, not only due to secession, but also because of migratory movements. The proportion of Muslims amounted to 60% in the 1820s, gradually increasing to 69% in the 1870s and then to 76% in the 1890s. By 1914, only 19.1% of the empire's population was non-Muslim, mostly made up of Christian Greeks, Assyrians, Armenians, and Jews.

Question:
What group ruled the empire until the 15th century?

a Muslim minority