From my BUI Grade 7-8 materials (back from the 1990's).
Navroz in Fatimid Egypt
According to Maqrizi when General Ghazi Jawhar entered Egypt in Shabaan 969 A.D, the country was already suffering from acute shortage of food due to one and half year old famine. The General arranged to bring grain from Qairawan. Hundreds of boats of grain arrived in due course but it did not help to ease the sitaution. Starvation and epidemic killed hundreds of thousands of people.
The subsequent winter season bruoght some relief. More grain cae fom Qairawan. The epidemic stopped too. The Egyptian welcomed the Fatimids as the angels of relief. At the end of the winter, they prepared lands for cultivation and after a long time celebrated the spring festival with renewed energy and enthusiasm. This became a regular annual celebration.
Later the Fatimid Caliphs used to take part in spring festivals with the peasants and farmers. Sweets and syrup were distributed. People wore colourful dresses and visited their relatives in a joyous mood.
Though the first eight Fatimid Caliphs of Egypt were Ismaili Imams who reigned from 969 - 1094 AD, but the ismailis remained as a minority group. Everyone was free to follow the religion of his choice. Therefore the spring festival remained as a festival of the peasants and farmers and not as an exlcusive Ismaili festival.
Nawroz as an Ismaili Festival
Actually the Ismailis have been celebrating Nawroz since the time of their Alamut period (1090 - 1256 AD) as a national festival. Most of the Ismailis were peasants of Persian origin. At the end of the dormant winter season they rejoiced looking forward to preparing their farms for good harvest. They turned to their Imam-e-Zaman for special blessings on that day of Navroz to invoke the Divine mercy for abundance.
Navroz is a great day of rejoicing. Everyone is in a joyous mood wishing each other "Navroz Mubarak" meaning a happy and properous New Year. Charity is given generously.
Navroz amound Indian Ismailis
Before the arrival of the forty-six Imam, the Aga Khan I; the jamat in India did not celebrate Navroz. In rural areas the Ismailis took part with the local communities in the 'wasant" (spring) festival particularly in the north.
Aga Khan I, came to India in 1842 A.D. with over two thousand people including his family, relatives and servants. It was sometime after his arrival that the jamat started celebrating Navroz as a communal festival with religious ceremonies.
In the beginning it started at th Aga Hall, the residence of the Imam in Bombay. The jamat went there to pay homage and to receive his blessings and rozi. Later, the Imam used to visit the jamat in Darkhana at Khadak in Bombay, and sometimes at the Jamat Khana in Poona.
Significance of Navroz
Navroz is the festival of great significance and has an age-old history among different peoples. Among the Ismailis, Navroz has been a important religious festival for the last 900 years since the Alamut period. The festival has also a social significance. Navroz is a day when special thanks are offered to the almight Allah. This is to mark the beginning of the New Year and to invoke him to bless us with abundance.
It is a day of reunion and renewing the ites and brotherhood/sisterhood. All friction and misunderstandgs are forgiven and forgotten. The spirit of service to others is revived in accordance with the Quranic words of "All momins are brothers"
People take stock on this day of their acheivements, set backs and shortcomings and make new resolutions and new efforts to progress in worldy and spiritual happiness.