The Boosey and Hawkes 'Emperor' bassoon with serial number 3629 was likely manufactured in the early to mid-20th century, as the company produced these instruments primarily between the 1940s and 1970s. To determine its exact age, you would need to consult Boosey and Hawkes' serial number records or reach out to a specialist in vintage instruments. Without specific records, it's difficult to give an exact age, but it could be estimated to be around 70-80 years old.