A beautiful and historically significant medal of the only King of England executed by an act of Parliament. 

The death memorial medal of Charles I of Great Britain, dated 1649, was indeed created by the Roettiers family, who were notable engravers and medalists. The Roettiers were a family of Flemish origin, and several members were active as engravers and medalists in England during the 17th century. The medal you are referring to commemorates the execution of King Charles I, which occurred on January 30, 1649.

These memorial medals were created as historical records and were often distributed to individuals who wanted to commemorate or remember the significant events of the time. They were not official currency but rather pieces of historical and artistic significance.

As with any historical medal, the value and collectability can depend on factors such as the condition of the medal, the specific die used in its production, and its rarity. Collectors interested in historical medals often seek out these items to add to their collections. If you have one of these Charles I death memorial medals, consulting with a numismatic expert or a reputable dealer can help provide more information about its specific characteristics and potential value in the current market.