Complex sentence: Until 1923 it was known as the City of London Hospital for Diseases of the Chest, then it was renamed the City of London Hospital for Diseases of the Heart and Lungs, although it was popularly known as the'Victoria Park Hospital'.
Split into simpler sentences: Until 1923 it was known as the City of London Hospital for Diseases of the Chest. In 1923 the Hospital was renamed the City of London Hospital for Diseases of the Heart and Lungs, although it was popularly known as the'Victoria Park Hospital'.