The first musical recordings were made on wax cylinders, simply known as "records" in their era of greatest popularity (1896–1915). These hollow cylindrical objects had an audio recording engraved on the outside surface, which could be reproduced when played on a mechanical cylinder phonograph. Entertainer J.K. Emmet (1841–91) was probably the most well-known yodeler of his time. He did make recordings but died before the recording industry was firmly established. Many future yodelers recorded songs he had either written or made popular, including "Sleep, Baby, Sleep". In the 1910s, the competing disc record system triumphed in the marketplace to become the dominant commercial audio medium.