On January 4, 1999 Nidai (2nd) Doshu Kisshomaru Ueshiba passed away. 2nd Doshu was instrumental in the international spread of Aikido. Without his contribution Aikido wouldn't be a prevalent today or widely enjoyed by millions of people.
Sensei was a student of 2nd Doshu and often told many stories about the time he spent with 2nd Doshu just after O Sensei passed away. One of my favorite stories Sensei told was about 2nd Doshu and the soda machine at Hombu dojo. One of the tasks Sensei was charged with while a deshi at Hombu Dojo was to stock the soda machine and count and turn in the money. One day while Sensei was counting the money he realized that someone had paid with a slug. When he brought this to Doshu's attention Doshu said, "I don't believe it. An Aikido person would never do such a thing. It must be someone from the outside." At first Sensei was in disbelief but later he realized how great of a teacher Doshu was because he believed wholeheartedly in his students.
Here is a video from 1957 of 2nd Doshu doing Aikido. https://www.youtube.com/watch?v=U9J9HoSZDkw