Bhosales of Nagpur began their campaign to liberate Jagannath Puri
On Vijayadashami, military campaign would start after worshipping weapons and the Shami tree.
Pandavas in Mahabharat had hid their weapons in a Shami tree and took them after their exile to go to war
Pic credit : ePhotoCorp
Theology apart, it made sound practical sense to launch campaigns from this date.
It usually falls in September - October.
Monsoons have ended, water bodies are full. Crops are standing or just harvested.
Roads are dry and accessible.
The monsoons was a difficult time to move around. Added to it was the problem of diseases and epidemics (which were common in cramped military camps of those days) .
The summers had their own problems.
Hence most campaigns began on Dusshera and arrived at their conclusion few months later in Feb - April period.
Painting : Mahishasur Mardini
Read about Palkhed and many other battles in Battles of the Maratha Empire
To understand the full enormity of this, read Battles of the Maratha Empire
Historians, much like Journalists, have eroded themselves over the past 70 years but indulging more in ideological bunkum than what their profession entails.
It is the reason why the "Professional Historian" gets no attention at best and his jeered at, at worst.
An invasion such as Somnath is also conveniently swept under some So Mannat fairy tale. Ghaznavi destroyed it because it protected the So Mannat idol from Arabia. Lulz.
Let me know if this was found anywhere in the textbooks :
The " Padarth" of the Jagannath Puri idols was chased by Kala Pahar all the way to Lake Chilka.
In fact there are many occasions that the murtis were moved.