The Will Makes The Way

He left a will to share his nineteen horses:
A half to his son; a quarter to daughter;
One fifth to his maid. Indivisible;
A wise man was sought, who came on his horse.

He placed his horses with nineteen horses.
Making it to twenty, he did as the will bid.
Ten to son, five to daughter and four to maid.
He took his. If will is there, way will form.