 Complete the following phrase:  Ajax is historically one of the most successful clubs in the world; according to the IFFHS, Ajax were the seventh-most successful European club of the 20th century. The club is one of the five teams that has earned the right to keep the European Cup and to wear a multiple-winner badge; they won consecutively in 19711973. In 1972, they completed the continental treble by winning the Eredivisie, KNVB Cup, and the European Cup. Ajaxs last international trophies were the 