Mystery of i

$latex \sqrt {-1} = i $ took 300 Years to be accepted.

1. 17AD - Cardano: (stole it from other) for cubic equation.

2. 18AD - Lebniz: i is like "Holy Spirit" between 'there' and 'not there'.

3. 19AD - Gauss: i as Geometry
Point (a,b) in plane RxR :
z=a+ib
a on x-axis, b on i-axis

4. 20AD - Hamilton:
i as ordered-pair (a,b) with unique operations:
(a, b)+(c,d)=(a+c, b+d)
(a, b).(c,d)=(ac-bd, bc+ad)