EM Fifth Avenue Q's sire Wertherson was foaled in Germany in 1983 and was 100-day tested at Adelheidsdorf in 1986. He was a son of the very popular Werther out of the States Premium mare Walesca by Waldhorn. Wertherson was a strikingly beautiful coppery chestnut stallion standing 16.3 hands. His sire Werther was awarded the first Hanoverian Stallion of the Year Award in Germany and because his FN rank for siring dressage, materiale, jumping and driving horses was at or near the top for nearly a decade, he earned the title of "Versatile Werther." Fifth has already produced 2 elite mares.
 

Wertherson himself was an extremely successful FEI competitor, and in his last year of competition earned a median score of over 65% at Prix St. Georges and over 66% at Intermediaire I. Wertherson has been recognized as a filly sire. He has to his credit numerous Elite Mares and many inspection site champion mares.