A History medial requires 7 full courses in history or its equivalent. Of those 7, four must be seminars. A History minor requires 5 full courses or its equivalent. No seminars are required for a minor. Typical Seminar Distribution in Undergraduate Programme.
Numbers differ because of numbering idiosyncrasies in the department.
No seminars are required for minors. You may fulfill all your concentration requirements by taking lecture courses. For that reason, minors will only be given places in seminars after majors and medials have received all their required seminars. At that time, you should simply go on Qcard to register for any seminars that still have spaces. Students should strive if possible to follow this normal pattern, but of course not all students will be able to do so.