Background of the Poltava battle
When Mazepa switched sides and allied Ukraine with Sweden Peter І was staying in Novgorod-Siversky, accompanied by all the high command of the army (warlords Menshikov and Sheremetyev), key figures of the government (chancellor Golovkin and his assistant Shafirov) and the former Russian ambassador in Poland (duke Dolgorukiy). That fact considerably facilitated a military engagement for tsar and enabled him to operate at a lightning speed.
Peter І took energetic steps. Already on October, 27 he published his first Manifesto to the Ukrainian people, which he notified in that Mazepa “was missing”. He ordered Cossack chieftains, colonels and "others" to immediately come to a conference and elect their new hetman in case "infidelity" of Mazepa would be confirmed. On October, 28 Peter І published the second Manifesto which he reported in about Mazepa’s treason and about his goal to pass "Little Russia Land" under the Polish domain again while giving all the churches to the Uniate believers. The tsar positioned himself as a defender of the Ukrainian people and even abolished some taxes for a demagogic purpose saying as if Mazepa had imposed those taxes in his favor. At the same time, the superior clergymen – metropolitan Ioasaf Krokovsky, Chernihiv archbishop Ivan Maksymovych and Cossack colonels – were promised to be "pardoned". So Peter І’s propagandist activities started, which B. Krupnytsky called "war of the Manifestos".
Ukraine was divided into two parts: the lesser one was occupied by the Swedish army, and the bigger one was under the power of the hetman Skoropadsky, which actually meant of Muscovy. Mazepa’s fears came true: Ukraine became the theatre of hostilities.
The civilians not preliminary prepared met the Swedish army as they usually meet invaders: mostly hostile. Have taken winter quarters, the Swedes required foods, fodder. It caused resistance among the population, which the Swedes responded their repressions to. Besides, Muscovite agents carried on permanent obstinate agitation and terror against those whom the Moscow government considered to be "Mazepa supporters".
The winter was an extremely severe and the Swedish army lacked accomodation and clothes resulted in mass illness. The Swedes had to assault towns of Piryatin, Smila,
Vepryk, Zinkiv whose dwellers did not want to let them come into.
Mazepa’s position got worsened. Many Cossack chieftains escaped to Peter I. It demoralized rank-and-file 
Cossacks who dispersed, too. There are incomplete Serdyuk and Kompaniyets regiments left.
The Swedes’ attempts to go east by expanding the war to the Slobidska Ukraine were unsuccessful.
The Swedes destroyed towns such as Krasnokutsk, Gorodnya, Kolomak, Kotelna, Murafa, Kolontaiv. The consequences were fatal for them: anti-Swedish guerilla warfare began.
The guerilla actions were oppressed by the Swedes which resulted in even bigger resistance of the locals. Thus, forces of the Swedish army were wasted to fight against the people, whose assistance Karl ХІІ hoped for while starting the campaign towards Ukraine.
All the above factors and also lack of the promised aid from Crimea, Turkey and Poland significantly worsened a position of the army of Charles XII. Only support of ataman K. Gordienko who joined the Swedish army at the head of 8,000-strong Cossack detachment in April 1709 somewhat improved the situation. In these conditions Karl XII decided to launch an offensive against Moscow through Kharkiv and Kursk. The substantial hindrance on this way was Poltava located at a crossing of the important roads. The town was defensed by a Russian garrison consisting of 4,300 persons and headed by a colonel A. Kelin and 2,600 habitants of the town, as well.
