The very first 4th degree exemplification was held at Lenox Lyceum in New York on February 22nd 1900. The 1400 new Patriotic knights traveled back to their home councils and started assemblies with members from their local and surrounding councils.
The Father William A. Schmitz assembly was instituted in August 1991 by Sir Knight John R Klein, Master of the District of Washington. There were 56 charter members that joined the new assembly from transfers from other assemblies and from an exemplification that was conferred in September 1991.
The assembly received their charter from the KC Supreme council on October 12th 1991. Does that date remind you of anything? The charter was signed by Supreme Master Darrell Beck.
As of October 12 2020, there are currently 61 assemblies in Washington State with 18 of those assemblies in the Eastern Washington district.