Europe's crucible of conflict that catapulted their militaries out of medieval times and into early modernity, was the Italian Wars. The Ottomans had their own: the conquests and reforms of Mehmed II, the conqueror of Constantinople.

Mehmed reorganized his army into a core of professionals (kapi kulu) - the most prominent being the Janissaries, but also including armored Spahi cavalry and artillery - and part timers (toprakli, and the levied-as-demanded miri-askari).

Janissaries formed the base of any Ottoman army facing Europeans. They were versatile infantry, armed and well trained in the use of muskets, but also carrying melee weapons and frequently armored, their favorite tactic was to blast enemy ranks into disorder with volleys, then charge in a mass for a decisive blow.

Turkish cavalry would guard the flanks and harry the rear of an opponent; the armored regulars were reserved for critical moments, whereas more light part time or levied cavalry proved ideal for raiding or horse archery. And always, the Ottoman artillery was in the rear providing supporting fire against any massed Christian formation, particularly pike and shot squares.

In front of the regular Janissaries would be part time or levied infantry called Azaps. Azap literally means "bachelor" and these men were light infantry, paid by the day they spent on campaign. Jacks of all trades, their job was to screen the main line, being armed with everything from bows to billhooks, slings to swords.

As opposed to European tactics, where the pikes are designed to keep opponents at a distance while constantly under musket fire, Ottoman tactics sought to screen their decisive heavy infantry with an all-arms curtain of threats, using cavalry, artillery, and versatile light infantry to get their Janisseries within range for a few thunderous volleys followed immediately by a concerted rush into any gap.

These tactics could of course be juggled, with any stationary European infantry being subjected to artillery fire while also being attrited by the Azaps from just outside pike range. European cavalry would be held up by the Azaps, while being hit by Janissary fire, and of course having to watch out for Spahi countercharges. And any broken or irregular formation was charged down by light Ottoman horse, or swept aside by the infantry push.

In summation, the Ottoman army of the 16th to mid 17th centuries was a force that utilized its mix of professional and levied forces to present a mix of threats to an opponent. In contrast to the stand off musketry of a tercio, the Ottomans sought to disrupt and overwhelm their enemies with a balance of units, ideally setting up a crushing fusillade followed by a decisive press of heavy infantry, followed by cavalry to complete the victory.

Sources: Uzunçarşılı, İsmail Hakkı, The Janissary and Turkish Society

Edward Erickson, A Military History of the Ottomans