Prince Philip has been married to Queen Elizabeth II for almost eight decades now. With this at hand, he also became the longest-serving consort in British history.

However, he recently stepped back from his royal duties and officially called in his retirement in 2017. While it became a shock to everyone, especially among fans and supporters, many individuals took it as a suitable decision for the Duke of Edinburgh given his age, not to mention, his unparalleled efforts for the monarchy.

As noted by the reports, the Queen's husband worked with her for 65 years. In those years, he was able to accomplish 637 solo trips across the globe with over 22,219 engagements, both official and not.

It was also added that during his service, he became a patron of more than 700 organizations worldwide. As for his appearances, he was reportedly able to deliver more than 5,400 speeches.

Today, Prince Philip is nearly approaching his 99th birthday. Although he is now residing in Sandringham, it was revealed that he always communicates with Queen Elizabeth II.

According to Express UK, the Queen's husband has a very wide range of interests. From technology and arts all the way to sports and outdoor activities, Prince Philip reportedly "loves" these things since then. But, aside from having such passion, the publication revealed that he is also an "incredible" collector of various items, especially art.

Amid his retirement, several sources from the publication shared that he is a "passionate collector" of "original political and royal cartoons." The majority of these cartoons were said to be in the Sandringham Estate.

As added by the reports, most of the pieces in his cartoon collection were drawn by the popular cartoonist, Carl Giles. Even so, he still reportedly shares praise and compliments to other cartoonists of today like, Matt Pritchett. 

The same publication also asserted that Prince Philip is not the first royal who collects cartoons. Based on claims, Kings George III and George IV were also passionate collectors of cartoons. While the Duke's sets are said to be in Norfolk, the collection sets of both late Kings are now "store in the Library of Congress."

It remains unknown today what Prince Philip has been doing in most of his time as a retired royal. Nevertheless, Daily Mail recently shared that he, as well as Queen Elizabeth II, were both spotted in Sandringham after the Megxit controversy. Although the deal was deemed to be the biggest controversy yet that allegedly shocked and stressed the Royal Family, the senior royal couple were reportedly looking much healthier today.