Saudi Arabia did not have it's own currency unit until 1928, it used gold english sovereigns and silver talers of Maria Theresia.
The riyal (as a silver coin) was introduced in January 1928 and it equalled 22 kershes. In 1948 the gold sovereign was declared a
legal tender with a fixed rate against the riyal. Beginning with September 1952 the Saudi sovereign was introduced, to replace
the english one. Beginning with 1960 the riyal equals 20 kershes and 100 halals.