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:
Middle_Ages

Context:
Among the results of the Greek and Islamic influence on this period in European history was the replacement of Roman numerals with the decimal positional number system and the invention of algebra, which allowed more advanced mathematics. Astronomy advanced following the translation of Ptolemy's Almagest from Greek into Latin in the late 12th century. Medicine was also studied, especially in southern Italy, where Islamic medicine influenced the school at Salerno.

Question:
What invention led to advances in mathematics?

algebra