Complex sentence: Under his Miller International Company formed in 1957 with his Essex Records office manager George Phillips, he founded Somerset Records and Somerset Stereo Fidelity Records that was his greatest claim to fame; selling large amounts of cheaply priced albums.
Split into simpler sentences: Under his Miller International Company formed in 1957 with his Essex Records office manager George Phillips, he founded Somerset Records and Somerset Stereo Fidelity Records budget albums. Miller's greatest claim to fame was selling large amounts of cheaply priced albums.