Registered by the B.O. Bracey Company is 1959, Rlc Memoria Crispin Rosales is what I would called a keystone plant for large Cattleya breeding ever since, with more than 1000 progeny registered. The ‘Behold’ cultivar was later awarded in 1983 with 6″ flowers and is very difficult to find nowadays. Becomes a pretty big plant that might not be practical for windowsill growing; of course I have no idea how big your windowsills are!
These plants are well-established in their 3.5″ pots where they have been growing for at least 6 months.