Of course, here is an overview of Belgium's heads of state from 1897 through 1920:

1. **Leopold II** (Reigned: 1865–1909): Leopold II was king of Belgium during this period. He ruled with a strong focus on the colonization of the Congo, which resulted in significant criticism of his regime for its exploitation of the country and its people.

2. **Albert I** (Reigned: 1909–1934): Albert I succeeded his uncle Leopold II as king in 1909. His reign was marked by the First World War, in which Belgium was heavily involved and in which Albert I was known for his courage and leadership.

These were the only two heads of state of Belgium during the period from 1897 to 1920.