On June 15, 1910, with the joint witness of many European royal family members, the "European Royal Family Union Declaration" was officially signed in London, the capital of the British Empire, and took effect immediately.
The Joint Declaration states that European royal families should protect the safety of all European royal family members, prohibit all regicide actions, and condemn all acts of assassinating royal family members.
If regicide occurs in any European royal family member's country after signing the declaration, other European royal families should unite to protect the royal family members of that country and restore its monarchy and social stability.
Although this is somewhat different from Arthur's idea of consolidating the monarchy and monarchist power in the world, it is still a protection for the royal families and monarchs of various countries.
