This is a basic introduction to the subject.
Even the most experienced collector or dealer in porcelain sometimes has difficulty in assessing when a particular piece was manufactured, but the following notes may be helpful in dating British porcelain and pottery from the mid 1800’s.
Pattern Name
Any printed mark incorporating the name of the pattern may be regarded as being subsequent to 1810

Royal Arms
 CRoyal Arms
 Any printed mark incorporating the Royal Arms or a version of the arms are 1800´s or later

The Royal Arms may only be used by businesses which are holders of a Royal Warrant. Nowadays Royal Warrants are granted to people or companies who have regularly supplied goods or services for a minimum of five consecutive years to members of the Royal Family.

However in the late 1800's and early 1900's many potters who did not have a Warrant, both in Britain and also foreign firms, also used the Arms or some similar design as part of their mark - to gain some sense of importance and value.

In the same way many potters use the name "Royal" as part of their name or trade mark.

From earliest times tradesmen and women have served their sovereign by providing goods and services – from making robes and regalia to repairing roofs and painting walls. The first rewards for this loyal service came in the form of Royal Charters which were granted to the trade guilds, later known as livery companies. The earliest recorded Royal Charter was granted to the Weavers’ Company in 1155 by Henry II. In 1394 Dick Whittington helped obtain a Royal Charter for his own Company, the Mercers, who traded in luxury fabrics.

By the 1400's Royal tradesmen were recognised by means of a Royal Warrant of Appointment - a practice that continues to this day.

In the late 1700's Warrant Holders began displaying the Royal Arms on their premises and stationery.

 However, it was Queen Victoria who ensured Royal Warrants gained the prestige they enjoy today. During her 64 year reign the Queen and her family were responsible for granting more Royal Warrants than ever before – more than 2000.
The function of the Royal Coat of Arms is to identify the person who is Head of State. In respect of the United Kingdom, the royal arms are borne only by the Sovereign.

They are used in many ways in connection with the administration and government of the country, for instance on coins, in churches and on public buildings. Queen Elizabeth the First instructed that all churches should have a royal coat of arms to symbolise the fact that the monarch was the head of the Church of England. They are familiar to most people as they appear on the products and goods of Royal Warrant holders.
 Church Royal Coat of Arms
The belt surrounding the shield bears the motto of the Order of the Garter, an ancient order of knighthood of which the Queen is Sovereign.

 "Hon Y Soit Qui Mal Y Pense" - "Shame to him who evil thinks"
Below is the motto of the Sovereign

 "Dieu et Mon Droit," - "God and My Right."
The Royal Coat of Arms of the United Kingdom have evolved over many years since the 1100's and reflect the history of the Monarchy and of the country, the arms have remained unchanged since Queen Victoria.
Royal Arms Shield 
The shield is supported by the English lion and Scottish unicorn.

The plant badges of the United Kingdom - rose, thistle and shamrock - are sometimes displayed beneath the shield.
Trade Mark
Trade Mark
Trade Marks signifies a date subsequent to the Trade Mark Act 1862 and usually denotes a date after 1875
Limited, Ld, Ltd etc indicates a date after 1860. It was not generally used in ceramic marks until 1880´s
Registered Number
Rd No followed by a number signifies a date after 1884. If the number is above 360, 000 the date is subsequent to 1900

England in a trademark was added from 1891 to comply with the American McKinrey Tariff Act.
It was William McKinley, the 25th president of the USA, who introduced the highly protectionist McKinley Tariff Act of 1890 - this imposed tariffs on many imports , including pottery, in order to make it easier for the American manufacturers to sell their products. It was a requirement of this Act that all such imports carried the name of the country of manufacture.

 This provided well-known marks such as "Bavaria," "England," "Nippon," - indicating the country of manufacture.
Made in England
Made In England denotes 1900’s manufacture.

In 1921 the American McKinrey Tariff Act. was amended to require the phrase "Made in" preceding the country of origin, The labelling at individual British potteries varies somewhat from the 1891/1921 dating requirements described above (e.g., Wedgwood adopted the "Made in England" around 1908/10 and may have used it on some pieces as early as 1898)

Bone China
Bone China in a trademark indicates 1900’s manufacture

Use of words of description such as "Ye Olde Willow" "Genuine Staffordshire Ware" "Victoria Ironstone" and the like usually indicate modern copies.

Microwave Proof
This is not a good indication that the piece is antique!!!!!!