Leopold Mozart, who was himself a talented musician, saw with pride almost beyond expression, that both of his children inherited his musical ability, and soon felt that Wolfgang was a genius. When the boy was only four, his father, to test his powers, tried to teach him some minuets which to his perfect astonishment, Wolfgang played after him in a most extraordinary manner, not merely striking the notes correctly, but marking the rhythm with accurate expression, and to learn and play each minuet the little fellow required only half an hour. When he was five years old, one day his father entered the sitting-room of their home and found Wolfgang bending over a table, writing so busily that he did not hear his father enter, or see that he was standing beside him. Wolfgang's chubby little hand held the pen awkwardly, but held it with firm determination while it travelled back and forth across a large sheet of paper on which he was scribbling a strange collection of hieroglyphics, with here and there a huge blot, testifying to his haste and inexperience in the use of ink. What was he trying to do? His father's curiosity finally overcame him and he asked: "What are you doing, Wolfgang?" The curly head was raised with an impatient gesture. "I am composing a concerto for the harpsichord. I have nearly finished the first part." "Let me see it." "No, please, I have not yet finished." But even as he spoke, the eager father had taken up the paper and carried it over to where a friend stood, and they looked it over together, exchanging amused glances at the queer characters on it. Presently Leopold Mozart, after looking carefully at it, said: "Why it really seems to be composed by rule! But it is so difficult that no one could ever play it." "Oh, yes, they could, but it must be studied first," exclaimed little Wolfgang eagerly, and running to the harpsichord, he added: "See, this is the way it begins," and he was able to play enough of it, to show what his idea in writing it had been, and his father and the friend who had before exchanged glances of amusement, now looked at each other with wonder not untouched with awe. In the Mozart collection at Salzburg, there is still preserved a music book in which those early pieces written by little Wolfgang were written down by his father, and also the minuets he learned, and in the book his father wrote after them: "The preceding minuets were learnt by Wolfgang in his fourth year," and further on we find the record: "This minuet and trio Wolfgang learned in half an hour on the 26th day of January, 1761, the day before his fifth birthday, at half-past nine at night." In his first composition the sense of perfect form is felt to a remarkable degree, and the little book in which it was written down, not only accompanied the family on their travels, but in it Wolfgang also wrote down his first sonatas, published in 1763.