elizabeth I

This is an excerpt from a short article precisely on this. You can check it out at the source-link below.

Throughout her reign, Parliament petitioned her to marry or nominate an heir to prevent civil war upon her death. She refused to do either. She kept this question open using it as a diplomatic ploy. Instead saying in 1563, “If I follow the inclination of my nature, it is this beggar-woman and single, far rather than queen and married”.

Here is another site that breaks her accomplishments down by point.

If I had to cite just one accomplishment that came as a result of Elizabeth's reign I couldn't do it.......... so I think I'll list two and be happy with that (her accomplishments are truly astounding).

During her reign, Elizabeth established a secure Church of England. The prior actions of her father, brother, and then sister had left the country in a religious uproar, whereas Elizabeth took it upon herself to insure that a compromise between Roman Catholicism and Protestantism was achieved and its 39 doctrines were lain down. Elizabeth said that she would not 'make windows into men's souls ... there is only one Jesus Christ and all the rest is a dispute over trifles'; she asked for outward uniformity; for the most part she got what she asked for. Her people accepted the compromise between the churches and the ensuing 39 doctrines as the basis of her faith. This accomplishment in itself saved the English people from religious wars like those fought in France not so very long after.

Equally important was Elizabeth's support of expeditions into the New World. These voyages were responsible for the important discoveries that enabled England to prepare for eventual colonization in America, and the expansion of trade that colonization would provide. Elizabeth herself realized the financial importance trade would have in England's future, and as a result she established the East India Company in 1600.