The League Of Nations could be seen as a success due to the three events they took charge in and were able to sort out. These events consisted of The Aaland Isalnds dispute in 1921 when Sweden and Finland both claimed the islands and were both willing to fight for this land yet when the League got involved they were able to come to a decision that the land was to be awarded to Finland. Both of the countries accepted what the League had decided and the problem was settled. The reason this was a success was that Sweden and Finland were both able to accept the decision that had been made. Essentially they stopped a war between the two countries and ended with a 'satisfactory outcome'.
Another event that occurred also in the 1920's was the economic collapse in Austria and Hungary in 1922. These countries faced bankruptcy and the League Of Nations organised international loans for them both but also commissioners were sent to control how the money was spent and therefore they were both able to economically recover. The League was a success in this occasion because they were able to help the two countries out of their economic collapse.
The Greek-Bulgarian dispute in 1925 was another factor that contributed to the League being a success as after the treaty of Neuilly the border between Greece and Bulgaria was a great cause of tension. The Greeks invaded Bulgaria in October 1925 but the League Of Nations intervened and stopped the Greeks from invading further and pressured them to withdraw which they finally did. The League was able to restore peace between the countries and avoid a possible war to occur which kept them both happy, meaning a success.
On the other hand the League could be seen as unsuccessful or a failure due to a different couple of events that also occurred in the 1920's but were seen to be treated unfairly by the League. The first event that happened in 1920 was a disagreement between