Long before the sherwani reached South Asia it was the dress code for noble men in Turkish and Persian courts. They were worn to show their subjects, each other and rival kingdoms their wealth, power and dignity.
As the Mughals conquered Indian, their way of dressing trickled down into the local Courts and the Maharajas began adopting the sherwani too. The Maharajas would have local craftsmen design and work on these sherwanis who began to change and adapt the clothing to local tastes with different styles of embroidery like zardozi and stonework than what had previously been seen. As with all Kings, the Maharajas would wear exquisite pieces made of the finest silks and gems whereas his subjects would wear simple clothing. The sherwani is truly clothing fit for a King.
As Mughal prestige began to fade, British influences found their way into Indian life. This greatly fractured land was easily conquered and India once again had new masters. The British bought about many changes and one of those changes was in the sherwani. Before every sherwani was an elaborate piece used to display the wearer's might and wealth but now some sherwanis began to resemble the British frock coat (a knee length, double breasted coat), that is to say, sherwanis were now being made without the heavy embellishments. They became plain and demure reflecting contemporary British views they turned into what we now call the achkan, a knee length coat with a mandarin collar.
After the partition of India and Pakistan, politicians on both sides favoured wearing sherwanis and achkan and made them popular amongst the people of both countries with sherwanis becoming the national dress for Pakistani men whilst in India they are worn mainly during weddings .