P&O Cruises has the oldest heritage of any cruise line in this directory. Its parent company began passenger operations in 1837, carrying mail and passengers from England to the Iberian Peninsula as the Peninsular Steam Navigation Company, became the Peninsular and Oriental Steam Navigation Company in 1840, and was offering leisure sailings by 1844. The modern P&O Cruises brand was formed in 1977, when P&O concentrated its passenger ships on cruising for the British market. The seven ships listed here are all large vessels built since 2000, ranging from the 76,152 GT Aurora, the fleet's traditional flagship in spirit, to the 185,581 GT Arvia. Between them sit the Grand-class Ventura and Azura, the Royal-class Britannia, and the Excellence-class pair Iona and Arvia, the largest ships built for the line.
The fleet — 7 ships in this directory
Sources: https://en.wikipedia.org/wiki/P%26O_Cruises