This is not modern Persian, so reading it would be a little hard for those who are not familiar enough with Persian language. I’ve translated it for you but if you need more help with some specific words, let me know

پس چنان افتاد که وقتي از ترکستان سپاهي گران بيامدند بقدر پنجاه هزار مرد، کار بجنگ افتاد، و اين ملک بر سر بلندي نشسته بود با تني چند از خاصگان خويش، دلش چنان خواست که آن روز جنگ با ديگر روز افگند، و بر پاره اي کاغذ نبشت که «سياه داران سپاه را بگويند تا باز گردند

...as it happened when a heavy troop came from Turkestan with an amount of 50000 men, a war occurred, and this(the) king was sitting on a high place surrounded by some of his retinues; he wanted to postpone the war for another day so he wrote on a piece of paper " order the troops to retreat'

Where did you get this text from? It's in a very beautiful classical Persian! 

you should do your homework by yourself :P

show us your translation, then ask for corrections. :)

Its a very old persian text...its about an arm which is around 50thousend  from turkamnistan go some where  to fighting but the king ask them to fight other day

mazyar  I am already translated it :P and understood the public meaning .. am just wanted to make sure of the translation >_<