The first confirmed mention of a Muslim community came from Marco Polo, the well-known traveler, who stopped in north Sumatra in 1292. Inscriptions and graves with Muslim dates have been located in others coastal areas along the trade routes. A major development was the decision of the ruler of Melaka, on the west coast of the Malay Peninsula, to adopt Islam around 1430. Melaka was a key trading center, and the Malay language, spoken in the Malay Peninsula and east Sumatra, was used as a lingua franca in trading ports throughout the Malay-Indonesian archipelago. Malay is not a difficult language to learn, and it was already understood by many people along the trade routes that linked the island world. Muslim teachers therefore had a common language through which they could communicate new concepts through oral presentations and written texts. A modified Arabic script displaced the previous Malay script. Arabic words were incorporated into Malay, particularly in regard to spiritual beliefs, social practices, and political life.