Half a semibreve is a minim. As a semibreve is the equivalent of 4 crotchets, a minim (a hollow oval with a stem) is therefore worth 2 crotchets. In America, the semibreve is refered to as 'whole' note and the minim as a 'half' note. Hope this helps!
Its half a semibreve which is two beats out of the four in one minum as a minum has two beats. Otherwise its two minums per semibreve which is 4. In short: Minum = 2 beats Semi = 4 beats 4/2 = 1/2 therefore half a semibreve per minum.
The semibreve is a symbol in modern music notation. The modern musical notation dates back to 1600s to the Baroque period. There is no exact person who introduced the semibreve, but presumably a baroque composer.
1 semibreve = 2 minims 1 minim = 2 crotchets 1 crotchet = 2 quavers 1 quaver = 2 semiquavers this means that there are 2 x 2 x 2 x 2 (=16) semiquavers in a semibreve So 1 semiquaver is equivalent to 1/16th of a semibreve