Construction of Office Buildings and Erection of New Cities Hazrat Umar (Rad.A) L»uilt a number of offices for various needs. The construction of prison in Makkah and Bait-ul-Mal in the Medina has been mentioned before. The Treasury Houses were also built in various provinces. The construction of the building of Treasury House (Bait-ul-Mal) was supervised by a Persian engineer ^ozbah who used the same type of cement in the building as was used :r. the palaces of the Persian Emperors. A number of rest-houses for travellers were also built. Hazrat Umar (Rad.A) also built many new roads and bridges. The road between Makkah and Medina was broadened and a number of rest-houses and police posts were built on this road. As described above a number of canals were constructed for irrigation and for supply of fresh water. A nine mile long canal was constructed in Basrah which brought water from the river Tigris. Some governors also built canals. Hazrat Sa’d bin Waqqas built a canal in Kufa. A number of new cities were founded. Special Care of Agriculture Agronomy was the main source of income during those days. Hazrat Umar (Rad.A) took special care of the welfare of agriculture and the farmers. As stated before he dug a number of canals for irrigation. A number of gardens were planted on his order. He made a law under which no Muslim could acquire land from the natives of the soil in the conquered territories. However land could be purchased. He supported both Muslim and non-Muslim farmers. Introduction of Islamic Calendar For the first time in the history of Islam, Calendar was introduced in the present form by Hazrat Umar (Rad.A). The date of start of this Calendar was fixed as the date of the ”Hijrah” (migration) of the Holy Prophet. Thus the Calendar is also known as the Hijrah Calendar.
