Commissioners: 

Lorenzo de' Medici 

(1 January 1449 – 9 April 1492) - the Ruler of Florence during Leonardo's life time. He contributed a lot to art and the artists and helped to fund and encourage the Renaissance. Leonardo says: "The Medici created and destroyed me." 

Ludovico Sforza

 Ludovico Sforza Aka: Ludovico il Moro 27 July 1452 – 27 May 1508) 1489-1508 Duke of Milan. commissioned theThe Last Supper.

Isabella_d'este

Attempted to commission for a painting but Leo only provided this sketch. Below are two letters she sent to him.  

To Master Leonardo Vinci, painter

Master Leonardo: Some months ago we wrote to you that we wanted to have a young Christ, about twelve years old, by your hand; you have replied through Messer Angelo Tovaglia that you would do this gladly; but owing to the many commissioned works you have on your hands, we doubt whether you have remembered ours. Wherefore, it has occurred to us to send you these few lines, begging you that when you are tired of the Florentine historical theme, you will turn to doing this little figure for us by way of recreation, which will be doing us a very gracious service and of benefit to yourself.

Farewell

Mantua, 31 October  1504

To Master Leonardo da Vinci, painter

Master Leonardo—Hearing that you are staying in Florence, we have conceived the hope that something we have long desired might come true: to have something by your hand. When you were here and drew our portrait in charcoal, you promised one day to do it in colour. But because this would be almost impossible, since it would be inconvenient for you to move here, we beg you to keep your good faith with us by substituting for our portrait another figure even more acceptable to us: that is, to do a youthful Christ of about twelve years old, which would be the age he was when he disputed with the doctors in the Temple, and executed with that sweetness and soft ethereal charm which is the peculiar excellence of your art. If we are gratified by you in this strong desire of ours, you shall know that beyond the payment, which you yourself shall fix, we shall remain so obliged to you that we shall think of nothing else but to do you good service, and from this very moment we offer ourselves to act at your convenience and pleasure. Expecting a favourable reply, we offer ourselves to do all your pleasure.

Mantua, 14 May 1504