okie ,let me explain
the 49 years timeline is not really timeline
Buddha spoke to many people on many occasion
to the Higher faculties - the Bodhisattvas
the average faulties - arhats and srvakas and lay community and the
royalties
the lower faculties - zhou li pan tie qie
the main 5 periods of teaching
He attained Enlightenment on the by deep samadhi and after His
struggle with Mara thousand army of desire, temptation and despair
.
at first in the first 49days ,He feels that the teaching He
awakened was too deep for any to understand ,and wish to enter
Parinirvana with Mara's request
The lord Brahma ,together with his retinue ,request Buddha
Sakyamuni to turn the wheel of Dharma for the sake of those who is
still suffering in the 6 realms of existence
the first period -Flower Adornment
on the first 3 - 7 days ,Buddha was in the Heavens talking to the
nagar(dragons) and Dieties
He preached the Assembly of Buddhalands which in chinese known as
Flower Adornment Sutra
the Adornment of Various Flowers symbolise all Mahasattvas and
Bodhisattvas and Buddhas specialising in their areas of Attainment
to periodical appear in the Saha world and other world to help
sentient beings
Next , Buddha realised that His few disciple are Sound-hearer
(sravaka ) and
renounce-affinity ( yuan jue ) are not able to understand the
Mahayana teaching of Greatness , so He start from the 4 Noble Truth
, the Noble Eightfold path , the 12 dependent originations
thus the turning of the wheel in Deer park(sarnath)
that is the Agama Period
then when the arhat have inspired the great path and many royalties
came along with Mahasattvas in the assembly , Buddha initiated the
period of teaching of Vaipulya Period (fang guang) means the
Magnamious and Greatness of the Great Vehicle in the path of
Bodhisattva to Buddhahood
third period ,Buddha teaches the Prajna period ,which He
specifically taken 22 years for the assembly on 10 occasion to
understand the whole concept of Emptiness
on the fourth period , which tientai also refers to akin to a Sun
at the 4pm-5pm , He teach the teachings of Dharma Flower Period
also known as Lotus Sutra
Finally as He about to enter Parinirvana,the final few years ,He
gives the teachings of nirvana Period ,in this period ,He
reiterates the teachings of the Great Vehicles ,the coming of
Buddha Maitreya ,the decline of Buddhism in future aeons exhort the
assembly to carry on the practice
His famous Last words is
"Subject to change are all things"
"Strive on with Dilligence"