Guarda Streamingcommunity. Queen Elizabeth The Second was the longest reigning monarch in British history. During her 70 years on the throne, Her Majesty has witnessed incredible change, and so did the nation she ruled over, but there was always a constant in her life: always by her side, Prince Philip was the man that offered her unconditional support and devotion. Through hardship and change, Elizabeth and Philip were inseparable for 73 years - their enduring love and unbreakable bond has been a staple of modern history.